Method of applying a buttress to a surgical stapler

ABSTRACT

A method of applying a buttress to a surgical stapler end effector comprises positioning a buttress assembly between an anvil and a staple cartridge of the end effector. The buttress assembly comprises a buttress body and an adhesive material. The adhesive material faces either an underside of the anvil or a deck of the staple cartridge. The anvil is in an open position relative to the staple cartridge during the act of positioning the buttress assembly between the anvil and the staple cartridge. The method further comprises moving the anvil toward the staple cartridge then moving the anvil back to the open position. The buttress assembly is adhered to the underside of the anvil or the deck of the staple cartridge via the adhesive material with the anvil moved back to the open position. The adhesive material comprises a bioabsorbable polymer.

This application is a continuation of U.S. patent application Ser. No.16/401,234, filed May 2, 2019 and published as U.S. Pub. No.2019/0314020 on Oct. 17, 2019, issued as U.S. Pat. No. 11,369,380 onJun. 28, 2022; which is a continuation of U.S. patent application Ser.No. 14/667,842, filed Mar. 25, 2015, and issued as U.S. Pat. No.10,349,939 on Jul. 16, 2019.

BACKGROUND

In some settings, endoscopic surgical instruments may be preferred overtraditional open surgical devices since a smaller incision may reducethe post-operative recovery time and complications. Consequently, someendoscopic surgical instruments may be suitable for placement of adistal end effector at a desired surgical site through the cannula of atrocar. These distal end effectors may engage tissue in a number of waysto achieve a diagnostic or therapeutic effect (e.g., endocutter,grasper, cutter, stapler, clip applier, access device, drug/gene therapydelivery device, and energy delivery device using ultrasonic vibration,RF, laser, etc.). Endoscopic surgical instruments may include a shaftbetween the end effector and a handle portion, which is manipulated bythe clinician. Such a shaft may enable insertion to a desired depth androtation about the longitudinal axis of the shaft, thereby facilitatingpositioning of the end effector within the patient. Positioning of anend effector may be further facilitated through inclusion of one or morearticulation joints or features, enabling the end effector to beselectively articulated or otherwise deflected relative to thelongitudinal axis of the shaft.

Examples of endoscopic surgical instruments include surgical staplers.Some such staplers are operable to clamp down on layers of tissue, cutthrough the clamped layers of tissue, and drive staples through thelayers of tissue to substantially seal the severed layers of tissuetogether near the severed ends of the tissue layers. Merely exemplarysurgical staplers are disclosed in U.S. Pat. No. 4,805,823, entitled“Pocket Configuration for Internal Organ Staplers,” issued Feb. 21,1989; U.S. Pat. No. 5,415,334, entitled “Surgical Stapler and StapleCartridge,” issued May 16, 1995; U.S. Pat. No. 5,465,895, entitled“Surgical Stapler Instrument,” issued Nov. 14, 1995; U.S. Pat. No.5,597,107, entitled “Surgical Stapler Instrument,” issued Jan. 28, 1997;U.S. Pat. No. 5,632,432, entitled “Surgical Instrument,” issued May 27,1997; U.S. Pat. No. 5,673,840, entitled “Surgical Instrument,” issuedOct. 7, 1997; U.S. Pat. No. 5,704,534, entitled “Articulation Assemblyfor Surgical Instruments,” issued Jan. 6, 1998; U.S. Pat. No. 5,814,055,entitled “Surgical Clamping Mechanism,” issued Sep. 29, 1998; U.S. Pat.No. 6,978,921, entitled “Surgical Stapling Instrument Incorporating anE-Beam Firing Mechanism,” issued Dec. 27, 2005; U.S. Pat. No. 7,000,818,entitled “Surgical Stapling Instrument Having Separate Distinct Closingand Firing Systems,” issued Feb. 21, 2006; U.S. Pat. No. 7,143,923,entitled “Surgical Stapling Instrument Having a Firing Lockout for anUnclosed Anvil,” issued Dec. 5, 2006; U.S. Pat. No. 7,303,108, entitled“Surgical Stapling Instrument Incorporating a Multi-Stroke FiringMechanism with a Flexible Rack,” issued Dec. 4, 2007; U.S. Pat. No.7,367,485, entitled “Surgical Stapling Instrument Incorporating aMultistroke Firing Mechanism Having a Rotary Transmission,” issued May6, 2008; U.S. Pat. No. 7,380,695, entitled “Surgical Stapling InstrumentHaving a Single Lockout Mechanism for Prevention of Firing,” issued Jun.3, 2008; U.S. Pat. No. 7,380,696, entitled “Articulating SurgicalStapling Instrument Incorporating a Two-Piece E-Beam Firing Mechanism,”issued Jun. 3, 2008; U.S. Pat. No. 7,404,508, entitled “SurgicalStapling and Cutting Device,” issued Jul. 29, 2008; U.S. Pat. No.7,434,715, entitled “Surgical Stapling Instrument Having MultistrokeFiring with Opening Lockout,” issued Oct. 14, 2008; U.S. Pat. No.7,721,930, entitled “Disposable Cartridge with Adhesive for Use with aStapling Device,” issued May 25, 2010; U.S. Pat. No. 8,408,439, entitled“Surgical Stapling Instrument with An Articulatable End Effector,”issued Apr. 2, 2013; and U.S. Pat. No. 8,453,914, entitled “Motor-DrivenSurgical Cutting Instrument with Electric Actuator Directional ControlAssembly,” issued Jun. 4, 2013. The disclosure of each of theabove-cited U.S. patents is incorporated by reference herein.

While the surgical staplers referred to above are described as beingused in endoscopic procedures, it should be understood that suchsurgical staplers may also be used in open procedures and/or othernon-endoscopic procedures. By way of example only, a surgical staplermay be inserted through a thoracotomy, and thereby between a patient'sribs, to reach one or more organs in a thoracic surgical procedure thatdoes not use a trocar as a conduit for the stapler. Such procedures mayinclude the use of the stapler to sever and close a vessel leading to alung. For instance, the vessels leading to an organ may be severed andclosed by a stapler before removal of the organ from the thoraciccavity. Of course, surgical staplers may be used in various othersettings and procedures.

Examples of surgical staplers that may be particularly suited or usethrough a thoracotomy are disclosed in U.S. Patent Pub. No.2014/0243801, entitled “Surgical Instrument End Effector ArticulationDrive with Pinion and Opposing Racks,” published Aug. 28, 2014, issuedas U.S. Pat. No. 9,186,142 on Nov. 17, 2015; U.S. Patent Pub. No.2014/0239041, entitled “Lockout Feature for Movable Cutting Member ofSurgical Instrument,” published Aug. 28, 2014, issued as U.S. Pat. No.9,717,497 on Aug. 1, 2017; U.S. Patent Pub. No. 2014/0239042, entitled“Integrated Tissue Positioning and Jaw Alignment Features for SurgicalStapler,” published Aug. 28, 2014, issued as U.S. Pat. No. 9,517,065 onDec. 13, 2016; U.S. Patent Pub. No. 2014/0239036, entitled “Jaw ClosureFeature for End Effector of Surgical Instrument,” published Aug. 28,2014, issued as U.S. Pat. No. 9,839,421 on Dec. 12, 2107; U.S. PatentPub. No. 2014/0239040, entitled “Surgical Instrument with ArticulationLock having a Detenting Binary Spring,” published Aug. 28, 2014, issuedas U.S. Pat. No. 9,867,615 on Jan. 16, 2018; U.S. Patent Pub. No.2014/0239043, entitled “Distal Tip Features for End Effector of SurgicalInstrument,” published Aug. 28, 2014, issued as U.S. Pat. No. 9,622,746on Apr. 18, 2017; U.S. Patent Pub. No. 2014/0239037, entitled “StapleForming Features for Surgical Stapling Instrument,” published Aug. 28,2014 issued as U.S. Pat. No. 10,092,292 on Oct. 9, 2017; U.S. PatentPub. No. 2014/0239038, entitled “Surgical Instrument with Multi-DiameterShaft,” published Aug. 28, 2014, issued as U.S. Pat. No. 9,795,379 onOct. 24, 2017; and U.S. Patent Pub. No. 2014/0239044, entitled“Installation Features for Surgical Instrument End Effector Cartridge,”published Aug. 28, 2014, issued as U.S. Pat. No. 9,808,248 on Nov. 17,2017. The disclosure of each of the above-cited U.S. Patent Publicationsis incorporated by reference herein.

Additional surgical stapling instruments are disclosed in U.S. Pat. No.8,141,762, entitled “Surgical Stapler Comprising a Staple Pocket,”issued Mar. 27, 2012; U.S. Pat. No. 8,371,491, entitled “Surgical EndEffector Having Buttress Retention Features,” issued Feb. 12, 2013; U.S.Pub. No. 2014/0263563, entitled “Method and Apparatus for SealingEnd-to-End Anastomosis” published Sep. 18, 2014, issued as U.S. Pat. No.9,597,082 on Mar. 21, 2017; U.S. Pub. No. 2014/0246473, entitled “RotaryPowered Surgical Instruments with Multiple Degrees of Freedom,”published Sep. 4, 2014, issued as U.S. Pat. No. 9,398,911 on Jul. 26,2016; U.S. Pub. No. 2013/0206813, entitled “Linear Stapler,” publishedAug. 15, 2013, now abandoned; U.S. Pub. No. 2008/0169328, entitled“Buttress Material for Use with a Surgical Stapler,” published Jul. 17,2008, now abandoned; U.S. patent application Ser. No. 14/300,804,entitled “Woven and Fibrous Materials for Reinforcing a Staple Line,”filed Jun. 10, 2014, issued as U.S. Pat. No. 9,848,871 on Dec. 26, 2017;U.S. patent application Ser. No. 14/300,811, entitled “Devices andMethods for Sealing Staples in Tissue”, issued as U.S. Pat. No.9,936,954 on Apr. 10, 2018; and U.S. patent application Ser. No.14/498,070, entitled “Radically Expandable Staple Line” filed Sep. 26,2014, published as U.S. Pub. No. 2016/0089146 on Mar. 31, 2016, issuedas U.S. Pat. No. 10,426,476 on Oct. 1, 2019. The disclosure of each ofthe above-cited U.S. Patents, U.S. Patent Publications, and U.S. PatentApplications is incorporated by reference herein.

In some instances, it may be desirable to equip a surgical staplinginstrument with a buttress material to reinforce the mechanicalfastening of tissue provided by staples. Such a buttress may prevent theapplied staples from pulling through tissue and may otherwise reduce arisk of tissue tearing at or near the site of applied staples.

While various kinds of surgical stapling instruments and associatedcomponents have been made and used, it is believed that no one prior tothe inventor(s) has made or used the invention described in the appendedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the invention,and, together with the general description of the invention given above,and the detailed description of the embodiments given below, serve toexplain the principles of the present invention.

FIG. 1 depicts a perspective view of an exemplary articulating surgicalstapling instrument;

FIG. 2 depicts a side elevational view of the instrument of FIG. 1 ;

FIG. 3 depicts a perspective view of an end effector of the instrumentof FIG. 1 , with the end effector in a closed configuration;

FIG. 4 depicts a perspective view of the end effector of FIG. 3 , withthe end effector in an open configuration;

FIG. 5 depicts an exploded perspective view of the end effector of FIG.3 ;

FIG. 6 depicts a cross-sectional end view of the end effector of FIG. 3, taken along line 6-6 of FIG. 4 ;

FIG. 7A depicts a cross-sectional side view of the end effector of FIG.3 , taken along line 7-7 of FIG. 4 , with a firing beam in a proximalposition;

FIG. 7B depicts a cross-sectional side view of the end effector of FIG.3 , taken along line 7-7 of FIG. 4 , with the firing beam in a distalposition;

FIG. 8 depicts a perspective view of the end effector of FIG. 3 ,positioned at tissue and having been actuated once in the tissue;

FIG. 9 depicts a cross-sectional view of an exemplary buttress assemblythat may be used with the end effector of FIG. 3 ;

FIG. 10 depicts an exploded perspective view of an exemplary buttressand retainer;

FIG. 11 depicts a perspective view of the buttress and retainer of FIG.10 , with the buttress secured to the underside of the retainer;

FIG. 12A depicts a side elevational view of the buttress and retainer ofFIG. 10 positioned for engagement with the end effector of FIG. 3 ;

FIG. 12B depicts a side elevational view of the buttress and retainer ofFIG. 10 engaging the end effector of FIG. 3 , with the anvil of the endeffector in an open position;

FIG. 12C depicts a side elevational view of the buttress and retainer ofFIG. 10 engaging the end effector of FIG. 3 , with the anvil of the endeffector moving toward a closed position;

FIG. 12D depicts a side elevational view of the retainer of FIG. 10being moved away from the end effector of FIG. 3 , with the buttress ofFIG. 10 being left behind on the end effector to form an end effectorand buttress assembly;

FIG. 13A depicts a cross-sectional view of a portion of the end effectorand buttress assembly of FIG. 12D, with tissue positioned between thebuttress and the anvil, and with the anvil in an open position;

FIG. 13B depicts a cross-sectional view of a portion of the end effectorand buttress assembly of FIG. 12D, with tissue positioned between thebuttress and the anvil, and with the anvil in a closed position;

FIG. 13C depicts a cross-sectional view of a staple and the buttress ofFIG. 12D being secured to tissue by the end effector of FIG. 12D;

FIG. 14 depicts a perspective view of staples and the buttress of FIG.12D having been secured to tissue by the end effector of FIG. 12D;

FIG. 15 depicts an exploded perspective view of an exemplary buttressand retainer;

FIG. 16 depicts a perspective view of the buttress and retainer of FIG.15 , with the buttress secured to the top side of the retainer;

FIG. 17A depicts a side elevational view of the buttress and retainer ofFIG. 15 positioned for engagement with the end effector of FIG. 3 ;

FIG. 17B depicts a side elevational view of the retainer of FIG. 15being moved away from the end effector of FIG. 3 , with the buttress ofFIG. 15 being left behind on the end effector to form an end effectorand buttress assembly;

FIG. 18A depicts a cross-sectional view of a portion of the end effectorand buttress assembly of FIG. 17B, with tissue positioned between thebuttress and the staple cartridge, and with the anvil in an openposition;

FIG. 18B depicts a cross-sectional view of a portion of the end effectorand buttress assembly of FIG. 17B, with tissue positioned between thebuttress and the staple cartridge, and with the anvil in a closedposition;

FIG. 18C depicts a cross-sectional view of a staple and the buttress ofFIG. 17B being secured to tissue by the end effector of FIG. 17B;

FIG. 19 depicts a perspective view of staples and the buttress of FIG.17B having been secured to tissue by the end effector of FIG. 17B;

FIG. 20 depicts a partial, cross-sectional, perspective view of a staplecartridge with an exemplary buttress assembly secured thereto;

FIG. 21 depicts a cross-sectional view of staples and a buttress securedto tissue;

FIG. 22A depicts a partial perspective view of a staple cartridge with abuttress being laid over exemplary retention features;

FIG. 22B depicts a partial perspective view of the staple cartridge ofFIG. 22A, with the buttress being pressed against the retention featuresto thereby secure the buttress to the staple cartridge;

FIG. 23 depicts an exploded perspective view of an exemplary alternativeretainer with a buttress positioned for engagement with an upper portionof the retainer;

FIG. 24A depicts a cross-sectional view of the retainer and buttress ofFIG. 23 , with an adhesive portion of the buttress positioned to contactthe anvil of the end effector of FIG. 3 , and with a post of theretainer spaced away from the buttress;

FIG. 24B depicts a cross-sectional view of the retainer and buttress ofFIG. 23 , with the post of the retainer driving the adhesive portion ofthe buttress into the anvil;

FIG. 24C depicts a cross-sectional view of the buttress of FIG. 23adhered to the anvil of the end effector of FIG. 3 , with the retainerremoved;

FIG. 25 depicts a perspective view of an exemplary alternative buttressassembly;

FIG. 26 depicts a perspective view of another exemplary alternativebuttress assembly;

FIG. 27 depicts a cross-sectional view of a region of the buttressassembly of FIG. 26 ;

FIG. 28 depicts a cross-sectional view of a region of the buttressassembly of FIG. 26 being compressed against the anvil of the endeffector of FIG. 3 ;

FIG. 29 depicts a perspective view of an exemplary alternative retainer;

FIG. 30 depicts an exploded cross-sectional view of an exemplarybuttress assembly between an exemplary retainer and the anvil of the endeffector of FIG. 3 ;

FIG. 31 depicts a perspective view of an exemplary alternative retainerassembly coupled with the end effector of FIG. 3 , with a syringeinjecting an adhesive material into the retainer assembly, and with theanvil of the end effector in an open position;

FIG. 32 depicts a cross-sectional view of the retainer assembly and endeffector of FIG. 31 ;

FIG. 33 depicts a perspective view of another exemplary alternativeretainer assembly coupled with the end effector of FIG. 3 , with asyringe injecting an adhesive material into the retainer assembly, andwith the anvil of the end effector in a closed position;

FIG. 34 depicts a perspective view of another exemplary alternativeretainer assembly coupled with the end effector of FIG. 3 , with anexemplary alternative syringe assembly positioned over the retainerassembly, and with the anvil of the end effector in an open position;

FIG. 35 depicts a cross-sectional side view of the syringe assembly ofFIG. 34 ;

FIG. 36 depicts a cross-sectional side view of an exemplary alternativebuttress assembly, with a protective layer being peeled away;

FIG. 37 depicts an exploded cross-sectional end view of the buttressassembly of FIG. 36 positioned between an exemplary retainer and theanvil of the end effector of FIG. 3 ;

FIG. 38 depicts a partial, exploded, perspective cross-sectional view ofan exemplary alternative staple cartridge with a buttress and retainer;

FIG. 39 depicts a cross-sectional end view of the staple cartridge,buttress, and retainer of FIG. 38 , with an additional buttress and ananvil in a closed position;

FIG. 40 depicts a cross-sectional view of the buttress of FIG. 38secured to the deck of the staple cartridge of FIG. 38 ;

FIG. 41 depicts a perspective view of an exemplary alternative retainerassembly;

FIG. 42 depicts a perspective view of a buttress assembly positioned onthe retainer assembly of FIG. 41 , with a protective layer being peeledaway from the buttress assembly;

FIG. 43A depicts a cross-sectional view of an exemplary buttressassembly in a first state of preparation;

FIG. 43B depicts a cross-sectional view of an exemplary buttressassembly in a second state of preparation;

FIG. 43C depicts a cross-sectional view of an exemplary buttressassembly in a third state of preparation;

FIG. 44 depicts an exploded cross-sectional view of the buttressassembly of FIG. 43C between an exemplary retainer and the anvil of theend effector of FIG. 3 ;

FIG. 45 depicts a perspective cross-sectional view of staples beingdriven through tissue and a buttress assembly;

FIG. 46A depicts a perspective cross-sectional view of a staple driventhrough tissue and a buttress assembly, at a stage immediately after thestaple has been driven through the tissue and buttress assembly;

FIG. 46B depicts a perspective cross-sectional view of a staple driventhrough tissue and a buttress assembly, at a stage where an adjunctmaterial has migrated into gaps around the staple legs;

FIG. 47 depicts an exploded, perspective cross-sectional view of anexemplary end effector assembly, retainer, and pair of buttressassemblies;

FIG. 48 depicts a partial perspective view of one of the buttressassemblies of FIG. 47 ;

FIG. 49 depicts a perspective view of some elements of one of thebuttress assemblies of FIG. 47 ;

FIG. 50 depicts a perspective view of an assembled form of one of thebuttress assemblies of FIG. 47 ;

FIG. 51 depicts a cross-sectional view of staples driven through tissueand the buttress assemblies of FIG. 47 ;

FIG. 52 depicts a perspective view of an exemplary alternative buttressassembly;

FIG. 53 depicts a cross-sectional end view of the buttress assembly ofFIG. 52 applied to the anvil of the end effector of FIG. 3 ;

FIG. 54 depicts a partial, cross-sectional perspective view of thebuttress assembly of FIG. 52 applied to the deck of the staple cartridgeof the end effector of FIG. 3 ;

FIG. 55 depicts a perspective view of an exemplary alternative buttressassembly;

FIG. 56 depicts a perspective view of another exemplary alternativebuttress assembly;

FIG. 57 depicts a perspective view of another exemplary alternativebuttress assembly; and

FIG. 58 depicts a perspective view of an exemplary alternative retainer.

The drawings are not intended to be limiting in any way, and it iscontemplated that various embodiments of the invention may be carriedout in a variety of other ways, including those not necessarily depictedin the drawings. The accompanying drawings incorporated in and forming apart of the specification illustrate several aspects of the presentinvention, and together with the description serve to explain theprinciples of the invention; it being understood, however, that thisinvention is not limited to the precise arrangements shown.

DETAILED DESCRIPTION

The following description of certain examples of the invention shouldnot be used to limit the scope of the present invention. Other examples,features, aspects, embodiments, and advantages of the invention willbecome apparent to those skilled in the art from the followingdescription, which is by way of illustration, one of the best modescontemplated for carrying out the invention. As will be realized, theinvention is capable of other different and obvious aspects, all withoutdeparting from the invention. Accordingly, the drawings and descriptionsshould be regarded as illustrative in nature and not restrictive.

I. Exemplary Surgical Stapler

FIG. 1 depicts an exemplary surgical stapling and severing instrument(10) that includes a handle assembly (20), a shaft assembly (30), and anend effector (40). End effector (40) and the distal portion of shaftassembly (30) are sized for insertion, in a nonarticulated state asdepicted in FIG. 1 , through a trocar cannula to a surgical site in apatient for performing a surgical procedure. By way of example only,such a trocar may be inserted in a patient's abdomen, between two of thepatient's ribs, or elsewhere. In some settings, instrument (10) is usedwithout a trocar. For instance, end effector (40) and the distal portionof shaft assembly (30) may be inserted directly through a thoracotomy orother type of incision. It should be understood that terms such as“proximal” and “distal” are used herein with reference to a cliniciangripping handle assembly (20) of instrument (10). Thus, end effector(40) is distal with respect to the more proximal handle assembly (20).It will be further appreciated that for convenience and clarity, spatialterms such as “vertical” and “horizontal” are used herein with respectto the drawings. However, surgical instruments are used in manyorientations and positions, and these terms are not intended to belimiting and absolute.

A. Exemplary Handle Assembly and Shaft Assembly

As shown in FIGS. 1-2 , handle assembly (20) of the present examplecomprises pistol grip (22), a closure trigger (24), and a firing trigger(26). Each trigger (24, 26) is selectively pivotable toward and awayfrom pistol grip (22) as will be described in greater detail below.Handle assembly (20) further includes an anvil release button (25), afiring beam reverse switch (27), and a removable battery pack (28).These components will also be described in greater detail below. Ofcourse, handle assembly (20) may have a variety of other components,features, and operabilities, in addition to or in lieu of any of thosenoted above. Other suitable configurations for handle assembly (20) willbe apparent to those of ordinary skill in the art in view of theteachings herein.

As shown in FIGS. 1-3 , shaft assembly (30) of the present examplecomprises an outer closure tube (32), an articulation section (34), anda closure ring (36), which is further coupled with end effector (40).Closure tube (32) extends along the length of shaft assembly (30).Closure ring (36) is positioned distal to articulation section (34).Closure tube (32) and closure ring (36) are configured to translatelongitudinally relative to handle assembly (20). Longitudinaltranslation of closure tube (32) is communicated to closure ring (36)via articulation section (34). Exemplary features that may be used toprovide longitudinal translation of closure tube (32) and closure ring(36) will be described in greater detail below.

Articulation section (34) is operable to laterally deflect closure ring(36) and end effector (40) laterally away from the longitudinal axis(LA) of shaft assembly (30) at a desired angle (a). End effector (40)may thereby reach behind an organ or approach tissue from a desiredangle or for other reasons. In some versions, articulation section (34)enables deflection of end effector (40) along a single plane. In someother versions, articulation section (34) enables deflection of endeffector along more than one plane. In the present example, articulationis controlled through an articulation control knob (35) which is locatedat the proximal end of shaft assembly (30). Knob (35) is rotatable aboutan axis that is perpendicular to the longitudinal axis (LA) of shaftassembly (30). Closure ring (36) and end effector (40) pivot about anaxis that is perpendicular to the longitudinal axis (LA) of shaftassembly (30) in response to rotation of knob (35). By way of exampleonly, rotation of knob (35) clockwise may cause corresponding clockwisepivoting of closure ring (36) and end effector (40) at articulationsection (34). Articulation section (34) is configured to communicatelongitudinal translation of closure tube (32) to closure ring (36),regardless of whether articulation section (34) is in a straightconfiguration or an articulated configuration.

In some versions, articulation section (34) and/or articulation controlknob (35) are/is constructed and operable in accordance with at leastsome of the teachings of U.S. Pub. No. 2014/0243801, entitled “SurgicalInstrument End Effector Articulation Drive with Pinion and OpposingRacks,” published Aug. 28, 2014, issued as U.S. Pat. No. 9,186,142 onNov. 17, 2015, the disclosure of which is incorporated by referenceherein. Articulation section (34) may also be constructed and operablein accordance with at least some of the teachings of U.S. patentapplication Ser. No. 14/314,125, entitled “Articulation Drive Featuresfor Surgical Stapler,” filed Jun. 25, 2014, published as U.S. Pub. No.2015/0374360 on Dec. 31, 2015, issued as U.S. Pat. No. 10,292,701 on May21, 2019, the disclosure of which is incorporated by reference herein;and/or in accordance with the various teachings below. Other suitableforms that articulation section (34) and articulation knob (35) may takewill be apparent to those of ordinary skill in the art in view of theteachings herein.

As shown in FIGS. 1-2 , shaft assembly (30) of the present examplefurther includes a rotation knob (31). Rotation knob (31) is operable torotate the entire shaft assembly (30) and end effector (40) relative tohandle assembly (20) about the longitudinal axis (LA) of shaft assembly(30). In some versions, rotation knob (31) is operable to selectivelylock the angular position of shaft assembly (30) and end effector (40)relative to handle assembly (20) about the longitudinal axis (LA) ofshaft assembly (30). For instance, rotation knob (31) may betranslatable between a first longitudinal position, in which shaftassembly (30) and end effector (40) are rotatable relative to handleassembly (20) about the longitudinal axis (LA) of shaft assembly (30);and a second longitudinal position, in which shaft assembly (30) and endeffector (40) are not rotatable relative to handle assembly (20) aboutthe longitudinal axis (LA) of shaft assembly (30). Of course, shaftassembly (30) may have a variety of other components, features, andoperabilities, in addition to or in lieu of any of those noted above. Byway of example only, at least part of shaft assembly (30) is constructedin accordance with at least some of the teachings of U.S. Pub. No.2014/0239038, entitled “Surgical Instrument with Multi-Diameter Shaft,”published Aug. 28, 2014, issued as U.S. Pat. No. 9,795,379 on Oct. 24,2017, the disclosure of which is incorporated by reference herein. Othersuitable configurations for shaft assembly (30) will be apparent tothose of ordinary skill in the art in view of the teachings herein.

B. Exemplary End Effector

As also shown in FIGS. 1-3 , end effector (40) of the present exampleincludes a lower jaw (50) and a pivotable anvil (60). Anvil (60)includes a pair of integral, outwardly extending pins (66) that aredisposed in corresponding curved slots (54) of lower jaw (50). Pins (66)and slots (54) are shown in FIG. 5 . Anvil (60) is pivotable toward andaway from lower jaw (50) between an open position (shown in FIGS. 2 and4 ) and a closed position (shown in FIGS. 1, 3, and 7A-7B). Use of theterm “pivotable” (and similar terms with “pivot” as a base) should notbe read as necessarily requiring pivotal movement about a fixed axis.For instance, in the present example, anvil (60) pivots about an axisthat is defined by pins (66), which slide along curved slots (54) oflower jaw (50) as anvil (60) moves toward lower jaw (50). In suchversions, the pivot axis translates along the path defined by slots (54)while anvil (60) simultaneously pivots about that axis. In addition orin the alternative, the pivot axis may slide along slots (54) first,with anvil (60) then pivoting about the pivot axis after the pivot axishas slid a certain distance along the slots (54). It should beunderstood that such sliding/translating pivotal movement is encompassedwithin terms such as “pivot,” “pivots,” “pivotal,” “pivotable,”“pivoting,” and the like. Of course, some versions may provide pivotalmovement of anvil (60) about an axis that remains fixed and does nottranslate within a slot or channel, etc.

As best seen in FIG. 5 , lower jaw (50) of the present example defines achannel (52) that is configured to receive a staple cartridge (70).Staple cartridge (70) may be inserted into channel (52), end effector(40) may be actuated, and then staple cartridge (70) may be removed andreplaced with another staple cartridge (70). Lower jaw (50) thusreleasably retains staple cartridge (70) in alignment with anvil (60)for actuation of end effector (40). In some versions, lower jaw (50) isconstructed in accordance with at least some of the teachings of U.S.Pub. No. 2014/0239044, entitled “Installation Features for SurgicalInstrument End Effector Cartridge,” published Aug. 28, 2014, issued asU.S. Pat. No. 9,808,248 on Nov. 7, 2017, the disclosure of which isincorporated by reference herein. Other suitable forms that lower jaw(50) may take will be apparent to those of ordinary skill in the art inview of the teachings herein.

As best seen in FIGS. 4-6 , staple cartridge (70) of the present examplecomprises a cartridge body (71) and a tray (76) secured to the undersideof cartridge body (71). The upper side of cartridge body (71) presents adeck (73), against which tissue may be compressed when anvil (60) is ina closed position. Cartridge body (71) further defines a longitudinallyextending channel (72) and a plurality of staple pockets (74). A staple(77) is positioned in each staple pocket (74). A staple driver (75) isalso positioned in each staple pocket (74), underneath a correspondingstaple (77), and above tray (76). As will be described in greater detailbelow, staple drivers (75) are operable to translate upwardly in staplepockets (74) to thereby drive staples (77) upwardly through staplepockets (74) and into engagement with anvil (60). Staple drivers (75)are driven upwardly by a wedge sled (78), which is captured betweencartridge body (71) and tray (76), and which translates longitudinallythrough cartridge body (71). Wedge sled (78) includes a pair ofobliquely angled cam surfaces (79), which are configured to engagestaple drivers (75) and thereby drive staple drivers (75) upwardly aswedge sled (78) translates longitudinally through cartridge (70). Forinstance, when wedge sled (78) is in a proximal position as shown inFIG. 7A, staple drivers (75) are in downward positions and staples (77)are located in staple pockets (74). As wedge sled (78) is driven to thedistal position shown in FIG. 7B by a translating knife member (80),wedge sled (78) drives staple drivers (75) upwardly, thereby drivingstaples (77) out of staple pockets (74) and into staple forming pockets(64) that are formed in the underside (65) of anvil (60). Thus, stapledrivers (75) translate along a vertical dimension as wedge sled (78)translates along a horizontal dimension.

It should be understood that the configuration of staple cartridge (70)may be varied in numerous ways. For instance, staple cartridge (70) ofthe present example includes two longitudinally extending rows of staplepockets (74) on one side of channel (72); and another set of twolongitudinally extending rows of staple pockets (74) on the other sideof channel (72). However, in some other versions, staple cartridge (70)includes three, one, or some other number of staple pockets (74) on eachside of channel (72). In some versions, staple cartridge (70) isconstructed and operable in accordance with at least some of theteachings of U.S. patent application Ser. No. 13/780,106, entitled“Integrated Tissue Positioning and Jaw Alignment Features for SurgicalStapler,” filed Feb. 28, 2013, issued as U.S. Pat. No. 9,517,065 on Dec.13, 2016, the disclosure of which is incorporated by reference herein.In addition or in the alternative, staple cartridge (70) may beconstructed and operable in accordance with at least some of theteachings of U.S. Pub. No. 2014/0239044, entitled “Installation Featuresfor Surgical Instrument End Effector Cartridge,” published Aug. 28,2014, issued as U.S. Pat. No. 9,808,248 on Nov. 7, 2017, the disclosureof which is incorporated by reference herein. Other suitable forms thatstaple cartridge (70) may take will be apparent to those of ordinaryskill in the art in view of the teachings herein.

As best seen in FIG. 4 , anvil (60) of the present example comprises alongitudinally extending channel (62) and a plurality of staple formingpockets (64). Channel (62) is configured to align with channel (72) ofstaple cartridge (70) when anvil (60) is in a closed position. Eachstaple forming pocket (64) is positioned to lie over a correspondingstaple pocket (74) of staple cartridge (70) when anvil (60) is in aclosed position. Staple forming pockets (64) are configured to deformthe legs of staples (77) when staples (77) are driven through tissue andinto anvil (60). In particular, staple forming pockets (64) areconfigured to bend the legs of staples (77) to secure the formed staples(77) in the tissue. Anvil (60) may be constructed in accordance with atleast some of the teachings of U.S. Pub. No. 2014/0239042, entitled“Integrated Tissue Positioning and Jaw Alignment Features for SurgicalStapler,” published Aug. 28, 2014, issued as U.S. Pat. No. 9,517,065 onDec. 13, 2016; at least some of the teachings of U.S. Pub. No.2014/0239036, entitled “Jaw Closure Feature for End Effector of SurgicalInstrument,” published Aug. 28, 2014, issued as U.S. Pat. No. 9,839,421on Dec. 12, 2017; and/or at least some of the teachings of U.S. Pub. No.2014/0239037, entitled “Staple Forming Features for Surgical StaplingInstrument,” published Aug. 28, 2014, issued as U.S. Pat. No. 10,092,292on Oct. 9, 2018 the disclosure of which is incorporated by referenceherein. Other suitable forms that anvil (60) may take will be apparentto those of ordinary skill in the art in view of the teachings herein.

In the present example, a knife member (80) is configured to translatethrough end effector (40). As best seen in FIGS. 5 and 7A-7B, knifemember (80) is secured to the distal end of a firing beam (82), whichextends through a portion of shaft assembly (30). As best seen in FIGS.4 and 6 , knife member (80) is positioned in channels (62, 72) of anvil(60) and staple cartridge (70). Knife member (80) includes a distallypresented cutting edge (84) that is configured to sever tissue that iscompressed between anvil (60) and deck (73) of staple cartridge (70) asknife member (80) translates distally through end effector (40). Asnoted above and as shown in FIGS. 7A-7B, knife member (80) also driveswedge sled (78) distally as knife member (80) translates distallythrough end effector (40), thereby driving staples (77) through tissueand against anvil (60) into formation. Various features that may be usedto drive knife member (80) distally through end effector (40) will bedescribed in greater detail below.

In some versions, end effector (40) includes lockout features that areconfigured to prevent knife member (80) from advancing distally throughend effector (40) when a staple cartridge (70) is not inserted in lowerjaw (50). In addition or in the alternative, end effector (40) mayinclude lockout features that are configured to prevent knife member(80) from advancing distally through end effector (40) when a staplecartridge (70) that has already been actuated once (e.g., with allstaples (77) deployed therefrom) is inserted in lower jaw (50). By wayof example only, such lockout features may be configured in accordancewith at least some of the teachings of U.S. Pub. No. 2014/0239041,entitled “Lockout Feature for Movable Cutting Member of SurgicalInstrument,” published Aug. 28, 2014, issued as U.S. Pat. No. 9,717,497on Aug. 1, 2017, the disclosure of which is incorporated by referenceherein; and/or at least some of the teachings of U.S. patent applicationSer. No. 14/314,108, entitled “Method of Using Lockout Features forSurgical Stapler Cartridge,” filed on Jun. 25, 2014, published as U.S.Pub. No. 2015/0374373 on Dec. 31, 2015, issued as U.S. Pat. No.10,355,147 on Jul. 2, 2019, the disclosure of which is incorporated byreference herein. Other suitable forms that lockout features may takewill be apparent to those of ordinary skill in the art in view of theteachings herein. Alternatively, end effector (40) may simply omit suchlockout features.

C. Exemplary Actuation of Anvil

In the present example, anvil (60) is driven toward lower jaw (50) byadvancing closure ring (36) distally relative to end effector (40).Closure ring (36) cooperates with anvil (60) through a camming action todrive anvil (60) toward lower jaw (50) in response to distal translationof closure ring (36) relative to end effector (40). Similarly, closurering (36) may cooperate with anvil (60) to open anvil (60) away fromlower jaw (50) in response to proximal translation of closure ring (36)relative to end effector (40). By way of example only, closure ring (36)and anvil (60) may interact in accordance with at least some of theteachings of U.S. Pub. No. 2014/0239036, entitled “Jaw Closure Featurefor End Effector of Surgical Instrument,” published Aug. 28, 2014,issued as U.S. Pat. No. 9,839,421 on Dec. 12, 2017, the disclosure ofwhich is incorporated by reference herein; and/or in accordance with atleast some of the teachings of U.S. patent application Ser. No.14/314,108, entitled “Jaw Opening Feature for Surgical Stapler,” filedon Jun. 25, 2014, published as U.S. Pub. No. 2015/0374373 on Dec. 31,2015, issued as U.S. Pat. No. 10,355,147 on Jul. 2, 2019, the disclosureof which is incorporated by reference herein. Exemplary features thatmay be used to provide longitudinal translation of closure ring (36)relative to end effector (40) will be described in greater detail below.

As noted above, handle assembly (20) includes a pistol grip (22) and aclosure trigger (24). As also noted above, anvil (60) is closed towardlower jaw (50) in response to distal advancement of closure ring (36).In the present example, closure trigger (24) is pivotable toward pistolgrip (22) to drive closure tube (32) and closure ring (36) distally.Various suitable components that may be used to convert pivotal movementof closure trigger (24) toward pistol grip (22) into distal translationof closure tube (32) and closure ring (36) relative to handle assembly(20) will be apparent to those of ordinary skill in the art in view ofthe teachings herein. When closure trigger (24) reaches a fully pivotedstate, such that anvil (60) is in a fully closed position relative tolower jaw (50), locking features in handle assembly (20) lock theposition of trigger (24) and closure tube (32), thereby locking anvil(60) in a fully closed position relative to lower jaw (50). Theselocking features are released by actuation of anvil release button (25).Anvil release button (25) is configured and positioned to be actuated bythe thumb of the operator hand that grasps pistol grip (22). In otherwords, the operator may grasp pistol grip (22) with one hand, actuateclosure trigger (24) with one or more fingers of the same hand, and thenactuate anvil release button (25) with the thumb of the same hand,without ever needing to release the grasp of pistol grip (22) with thesame hand. Other suitable features that may be used to actuate anvil(60) will be apparent to those of ordinary skill in the art in view ofthe teachings herein.

D. Exemplary Actuation of Firing Beam

In the present example, instrument (10) provides motorized control offiring beam (82). In particular, instrument (10) includes motorizedcomponents that are configured to drive firing beam (82) distally inresponse to pivoting of firing trigger (26) toward pistol grip (22). Insome versions, a motor (not shown) is contained in pistol grip (22) andreceives power from battery pack (28). This motor is coupled with atransmission assembly (not shown) that converts rotary motion of a driveshaft of the motor into linear translation of firing beam (82). In somesuch versions, firing beam (82) may only be advanced distally when anvil(60) is in a fully closed position relative to lower jaw (50). Afterfiring beam (82) is advanced distally to sever tissue and drive staples(77) as described above with reference to FIGS. 7A-7B, the driveassembly for firing beam (82) may be automatically reversed to drivefiring beam (82) proximally back to the retracted position (e.g., backfrom the position shown in FIG. 7B to the position shown in FIG. 7A).Alternatively, the operator may actuate firing beam reverse switch (27),which may reverse the drive assembly for firing beam (82) in order toretract firing beam (82) to a proximal position. Handle assembly (20) ofthe present example further includes a bailout feature (21), which isoperable to provide a mechanical bailout allowing the operator tomanually retract firing beam (82) proximally (e.g., in the event ofpower loss while firing beam (82) is in a distal position, etc.).

By way of example only, the features that are operable to providemotorized actuation of firing beam (82) may be configured and operablein accordance with at least some of the teachings of U.S. Pat. No.8,210,411, entitled “Motor-Driven Surgical Instrument,” issued Jul. 3,2012, the disclosure of which is incorporated by reference herein. Asanother merely illustrative example, the features that are operable toprovide motorized actuation of firing beam (82) may be configured andoperable in accordance with at least some of the teachings of U.S. Pat.No. 8,453,914, entitled “Motor-Driven Surgical Cutting Instrument withElectric Actuator Directional Control Assembly,” issued Jun. 4, 2013,the disclosure of which is incorporated by reference herein. As yetanother merely illustrative example, the features that are operable toprovide motorized actuation of firing beam (82) may be configured andoperable in accordance with at least some of the teachings of U.S.patent application Ser. No. 14/226,142, entitled “Surgical InstrumentComprising a Sensor System,” filed Mar. 26, 2014, issued as U.S. Pat.No. 9,913,642 on Mar. 13, 2018, the disclosure of which is incorporatedby reference herein.

Other suitable components, features, and configurations that may be usedto provide motorization of firing beam (82) will be apparent to those ofordinary skill in the art in view of the teachings herein. It shouldalso be understood that some other versions may provide manual drivingof firing beam (82), such that a motor may be omitted. By way of exampleonly, firing beam (82) may be manually actuated in accordance with atleast some of the teachings of any other reference cited herein.

FIG. 8 shows end effector (40) having been actuated through a singlestroke through tissue (90). As shown, cutting edge (84) (obscured inFIG. 8 ) has cut through tissue (90), while staple drivers (75) havedriven two alternating rows of staples (77) through the tissue (90) oneach side of the cut line produced by cutting edge (84). Staples (77)are all oriented substantially parallel to the cut line in this example,though it should be understood that staples (77) may be positioned atany suitable orientations. In the present example, end effector (40) iswithdrawn from the trocar after the first stroke is complete, the spentstaple cartridge (70) is replaced with a new staple cartridge (70), andend effector (40) is then again inserted through the trocar to reach thestapling site for further cutting and stapling. This process may berepeated until the desired amount of cuts and staples (77) have beenprovided. Anvil (60) may need to be closed to facilitate insertion andwithdrawal through the trocar; and anvil (60) may need to be opened tofacilitate replacement of staple cartridge (70).

It should be understood that cutting edge (84) may cut tissuesubstantially contemporaneously with staples (77) being driven throughtissue during each actuation stroke. In the present example, cuttingedge (84) just slightly lags behind driving of staples (77), such that astaple (47) is driven through the tissue just before cutting edge (84)passes through the same region of tissue, though it should be understoodthat this order may be reversed or that cutting edge (84) may bedirectly synchronized with adjacent staples. While FIG. 8 shows endeffector (40) being actuated in two layers (92, 94) of tissue (90), itshould be understood that end effector (40) may be actuated through asingle layer of tissue (90) or more than two layers (92, 94) of tissue.It should also be understood that the formation and positioning ofstaples (77) adjacent to the cut line produced by cutting edge (84) maysubstantially seal the tissue at the cut line, thereby reducing orpreventing bleeding and/or leaking of other bodily fluids at the cutline. Furthermore, while FIG. 8 shows end effector (40) being actuatedin two substantially flat, apposed planar layers (92, 94) of tissue, itshould be understood that end effector (40) may also be actuated acrossa tubular structure such as a blood vessel, a section of thegastrointestinal tract, etc. FIG. 8 should therefore not be viewed asdemonstrating any limitation on the contemplated uses for end effector(40). Various suitable settings and procedures in which instrument (10)may be used will be apparent to those of ordinary skill in the art inview of the teachings herein.

It should also be understood that any other components or features ofinstrument (10) may be configured and operable in accordance with any ofthe various references cited herein. Additional exemplary modificationsthat may be provided for instrument (10) will be described in greaterdetail below. Various suitable ways in which the below teachings may beincorporated into instrument (10) will be apparent to those of ordinaryskill in the art. Similarly, various suitable ways in which the belowteachings may be combined with various teachings of the references citedherein will be apparent to those of ordinary skill in the art. It shouldtherefore be understood that the teachings below may be readilyincorporated into the various instruments taught in the variousreferences that are cited herein. It should also be understood that thebelow teachings are not limited to instrument (10) or devices taught inthe references cited herein. The below teachings may be readily appliedto various other kinds of instruments, including instruments that wouldnot be classified as surgical staplers. Various other suitable devicesand settings in which the below teachings may be applied will beapparent to those of ordinary skill in the art in view of the teachingsherein.

II. Exemplary Buttress for Surgical Stapler

As noted above, it may be desirable in some instances to equip endeffector (40) with a buttress material to reinforce the mechanicalfastening of tissue (90) provided by staples (77). Such a buttress mayprevent the applied staples (77) from pulling through tissue (90) andmay otherwise reduce a risk of tissue (90) tearing at or near the siteof applied staples (77). In addition to or as an alternative toproviding structural support and integrity to a line of staples (77), abuttress may provide various other kinds of effects such as spacing orgap-filling, administration of therapeutic agents, and/or other effects.In some instances, a buttress may be provided on deck (73) of staplecartridge (70). In some other instances, a buttress may be provided onthe surface of anvil (60) that faces staple cartridge (70). It shouldalso be understood that a first buttress may be provided on deck (73) ofstaple cartridge (70) while a second buttress is provided on anvil (60)of the same end effector (40). Various examples of forms that a buttressmay take will be described in greater detail below. Various ways inwhich a buttress may be secured to a staple cartridge (70) or an anvil(60) will also be described in greater detail below.

A. Exemplary Composition of Buttress for Surgical Stapler

FIG. 9 shows an exemplary buttress assembly (100) with a basiccomposition. Buttress assembly (100) of this example comprises abuttress body (102), an upper adhesive layer (104), and a lower adhesivelayer (106). In the present example, buttress body (102) comprises astrong yet flexible material configured to structurally support a lineof staples (77). In addition or in the alternative, buttress body (102)may comprise a material including, for example, a hemostatic agent suchas fibrin to assist in coagulating blood and reduce bleeding at thesevered and/or stapled surgical site along tissue (90).

As another merely illustrative example, buttress body (102) may compriseother adjuncts or hemostatic agents such as thrombin may be used suchthat buttress body (102) may assist to coagulate blood and reduce theamount of bleeding at the surgical site. The hemostatic abilities ofsuch adjuncts may also contribute to the use of such adjuncts asadhesives and sealants. The agents may assist to coagulate blood at asurgical site, which allows tissue surrounding such blood to sticktogether and may prevent leaks along the stapled tissue site, forexample. Other adjuncts or reagents that may be incorporated intobuttress body (102) may further include but are not limited to medicalfluid or matrix components. By way of example only, buttress body (102)may include natural or genetically engineered absorbable polymers orsynthetic absorbable polymers, or mixtures thereof. Merely illustrativeexamples of natural or genetically engineered absorbable polymers areproteins, polysaccharides and combinations thereof. Merely illustrativeexamples of proteins that may be used include prothrombin, thrombin,fibrinogen, fibrin, fibronectin, heparinase, Factor X/Xa, FactorVII/VIIa, Factor IX/IXa, Factor XI/XIa, Factor XII/XIIa, tissue factor,batroxobin, ancrod, ecarin, von Willebrand Factor, collagen, elastin,albumin, gelatin, platelet surface glycoproteins, vasopressin,vasopressin analogs, epinephrine, selectin, procoagulant venom,plasminogen activator inhibitor, platelet activating agents, syntheticpeptides having hemostatic activity, and/or combinations thereof.Polysaccharides include, without limitation, cellulose, alkyl cellulose,e.g. methylcellulose, alkylhydroxyalkyl cellulose, hydroxyalkylcellulose, cellulose sulfate, salts of carboxymethyl cellulose,carboxymethyl cellulose, carboxyethyl cellulose, chitin, carboxymethylchitin, hyaluronic acid, salts of hyaluronic acid, alginate, alginicacid, propylene glycol alginate, glycogen, dextran, dextran sulfate,curdlan, pectin, pullulan, xanthan, chondroitin, chondroitin sulfates,carboxymethyl dextran, carboxymethyl chitosan, chitosan, heparin,heparin sulfate, heparan, heparan sulfate, dermatan sulfate, keratansulfate, carrageenans, chitosan, starch, amylose, amylopectin,poly-N-glucosamine, polymannuronic acid, polyglucuronic acidpolyguluronic acid, and derivatives of any of the above. Examples ofsynthetic absorbable polymers are aliphatic polyester polymers,copolymers, and/or combinations thereof. The aliphatic polyesters aretypically synthesized in a ring opening polymerization of monomersincluding, but not limited to, lactic acid, lactide (including L-, D-,meso and D, L mixtures), glycolic acid, glycolide, ε-caprolactone,p-dioxanone (1,4-dioxan-2-one), and trimethylene carbonate(1,3-dioxan-2-one). Other suitable compounds, materials, substances,etc., that may be used in a medical fluid or matrix will be apparent tothose of ordinary skill in the art in view of the teachings herein.

Buttress body (102) may alternatively comprise a fibrous pad, a foam, amesh, a weave, and/or another structure capable of containing anadhesive and/or other type of medical fluid. In addition or in thealternative, buttress body (102) may simply comprise a mesh, a weave,and/or some other structure that is constructed to provide structuralsupport or integrity to a line of staples (77) applied through tissue(90). Such a material and structure may be relatively thin and in someinstances may be substantially non-compressible. By way of furtherexample only, buttress body (102) may be constructed in accordance withat least some of the teachings of U.S. Patent Pub. No. 2012/0241493,entitled “Tissue Thickness Compensator Comprising Controlled Release andExpansion,” published Sep. 27, 2012, issued as U.S. Pat. No. 10,123,798on Nov. 13, 2018, the disclosure of which is incorporated by referenceherein; U.S. Patent Pub. No. 2013/0068816, entitled “Surgical Instrumentand Buttress Material,” published Mar. 21, 2013, now abandoned, thedisclosure of which is incorporated by reference herein; U.S. PatentPub. No. 2013/0062391, entitled “Surgical Instrument with Fluid FillableButtress,” published Mar. 14, 2013, issued as U.S. Pat. No. 9,999,408 onJun. 19, 2018, the disclosure of which is incorporated by referenceherein; U.S. Patent Pub. No. 2013/0068820, entitled “Fibrin Pad Matrixwith Suspended Heat Activated Beads of Adhesive,” published Mar. 21,2013, issued as U.S. Pat. No. 8,814,025 on Aug. 26, 2014, the disclosureof which is incorporated by reference herein; U.S. Patent Pub. No.2013/0082086, entitled “Attachment of Surgical Staple Buttress toCartridge,” published Apr. 4, 2013, issued as U.S. Pat. No. 8,899,464 onDec. 2, 2014, the disclosure of which is incorporated by referenceherein; U.S. Patent Pub. No. 2013/0037596, entitled “Device for ApplyingAdjunct in Endoscopic Procedure,” published Feb. 14, 2013, issued asU.S. Pat. No. 9,492,170 on Nov. 15, 2016, the disclosure of which isincorporated by reference herein; U.S. Patent Pub. No. 2013/0062393,entitled “Resistive Heated Surgical Staple Cartridge with Phase ChangeSealant,” published Mar. 14, 2013, issued as U.S. Pat. No. 8,998,060 onApr. 7, 2015, the disclosure of which is incorporated by referenceherein; U.S. Patent Pub. No. 2013/0075446, entitled “Surgical StapleAssembly with Hemostatic Feature,” published Mar. 28, 2013, issued asU.S. Pat. No. 9,383,018 on Jul. 19, 2016, the disclosure of which isincorporated by reference herein; U.S. Patent Pub. No. 2013/0062394,entitled “Surgical Staple Cartridge with Self-Dispensing StapleButtress,” published Mar. 14, 2013, issued as U.S. Pat. No. 9,101,359 onAug. 11, 2015, the disclosure of which is incorporated by referenceherein; U.S. Patent Pub. No. 2013/0075445, entitled “Anvil Cartridge forSurgical Fastening Device,” published Mar. 28, 2013, issued as U.S. Pat.No. 9,198,644 on Dec. 1, 2015, the disclosure of which is incorporatedby reference herein; U.S. Patent Pub. No. 2013/0075447, entitled“Adjunct Therapy for Applying Hemostatic Agent,” published Mar. 28,2013, now abandoned, the disclosure of which is incorporated byreference herein; and/or U.S. Patent Pub. No. 2013/0256367, entitled“Tissue Thickness Compensator Comprising a Plurality of Medicaments,”published Oct. 3, 2013, issued as U.S. Pat. No. 9,211,120 on Dec. 15,2015, the disclosure of which is incorporated by reference herein.

In the present example, buttress body (102) comprises a woven mesh ofVICRYL® (polyglactin 910) material by Ethicon US, LLC. VICRYL® wovenmesh is prepared from a synthetic absorbable copolymer of glycolide andlactide, derived respectively from glycolic and lactic acids. Thistightly woven mesh is prepared from uncoated, undyed fiber identical incomposition to that used in VICRYL® synthetic absorbable suture, whichhas been found to be inert, nonantigenic, nonpyrogenic, and to elicitonly a mild tissue reaction during absorption. VICRYL® woven mesh isintended for use as a buttress to provide temporary support during thehealing process. Alternatively, any other suitable materials orcombinations of materials may be used in addition to or as analternative to VICRYL® material to form buttress body (102).

In versions where buttress body (102) is formed as a mesh, it should beunderstood that various kinds of mesh geometry may be used. By way ofexample only, buttress body (102) may be formed as a woven mesh, aknitted mesh, or a warp knitted mesh. Regardless of whether buttressbody (102) is formed as a mesh or not, buttress body (102) is porous insome examples. As described in greater detail below, an adhesive layer(104, 106) may be provided on buttress body (102) in order to adherebuttress body (102) to underside (65) of anvil (60) or deck (73) ofstaple cartridge (70). In some versions where buttress body (102) isporous, the material forming adhesive layer (104, 106) may pass throughbuttress body (102) to reach the outer surface of buttress body (102)that is opposite to the surface on which adhesive layer (104, 106) isdisposed.

By way of example only, upper adhesive layer (104) may be used to securebuttress assembly (100) to the underside (304) of a retainer (300) aswill be described in greater detail below; while lower adhesive layer(106) is used to secure buttress assembly (100) to deck (73) of staplecartridge (70). In some versions of this example, lower adhesive layer(106) is configured to provide stronger adherence than upper adhesivelayer (104). In some illustrative variations of this example, one ormore features of retainer (300) (e.g., flanges, clips, etc.) areconfigured to selectively retain buttress assembly (100) againstunderside (304) of retainer (300), such that upper adhesive layer (104)is omitted; while lower adhesive layer (106) is used to secure buttressassembly (100) to deck (73) of staple cartridge (70). In addition or inthe alternative, an adhesive material may be applied to the lowersurface of a porous version of buttress body (102) to form loweradhesive layer (106), and some of that adhesive material may passthrough buttress body (102) to form upper adhesive layer (104). In somesuch versions, lower adhesive layer (106) ultimately has more adhesivematerial than upper adhesive layer (104), such that lower adhesive layer(106) provides greater adhesion than upper adhesive layer (104).

In yet another merely illustrative example, lower adhesive layer (106)may be used to secure buttress assembly (100) to the upper side (302) ofa retainer (300) as will be described in greater detail below; whileupper adhesive layer (104) is used to secure buttress assembly tounderside (65) of anvil (60) of end effector (40). In some versions ofthis example, upper adhesive layer (104) is configured to providestronger adherence than lower adhesive layer (106). In some illustrativevariations of this example, one or more features of retainer (300)(e.g., flanges, clips, etc.) are configured to selectively retainbuttress assembly (100) against upper side (302) of retainer (300), suchthat lower adhesive layer (106) is omitted; while upper adhesive layer(104) is used to secure buttress assembly (100) to underside (65) ofanvil (60). In addition or in the alternative, an adhesive material maybe applied to the upper surface of a porous version of buttress body(102) to form upper adhesive layer (104), and some of that adhesivematerial may pass through buttress body (102) to form lower adhesivelayer (106). In some such versions, upper adhesive layer (104)ultimately has more adhesive material than lower adhesive layer (106),such that upper adhesive layer (104) provides greater adhesion thanlower adhesive layer (106).

Various suitable compositions that may be used to form each adhesivelayer (104, 106), as well as various forms that each adhesive layer(104, 106) may take, will be described in greater detail below.

It should also be understood that buttress assembly (100) may include animpermeable layer or a semi impermeable layer interposed betweenbuttress body (102) and adhesive layer (102), to prevent or restrictmigration of adhesive material from adhesive layer (104, 106) intobuttress body (100). By way of example only, body (102) may be formed ofa porous media (e.g., ETHISORB™ by Codman of Raynham, Mass.); while thesemi impermeable layer may comprise polydioxanone (PDS). In versionswhere buttress assembly (100) comprises an impermeable layer or a semiimpermeable layer to prevent or restrict migration of adhesive materialfrom adhesive layer (104, 106) into buttress body (100), such a layermay be integrated into buttress body (102) such that the layer permitsthe adhesive to migrate at least partially into buttress body (102) butnot across the full thickness of buttress body (102). Various suitableways in which an impermeable layer or a semi impermeable layer may beintegrated into buttress assembly (100) to prevent or restrict migrationof an adhesive material will be apparent to those of ordinary skill inthe art in view of the teachings herein.

B. Exemplary Instrument and Technique for Securing Buttress to Deck ofStaple Cartridge

FIGS. 10-12D show a combination of an exemplary buttress (200) with anexemplary retainer (300). Buttress (200) of this example may beconstructed in accordance with the teachings above relating to buttressassembly (100) and/or in accordance with other teachings herein.Buttress (200) includes an upper side (202) and an underside (204). Inthe present example, underside (204) includes an adhesive (e.g., likelower adhesive layer (106)) to secure buttress (200) to deck (73) ofstaple cartridge (70) as described in greater detail below.

Retainer (300) of this example comprises an upper side (302), anunderside (304), a distally projecting tongue (306), and a set ofresilient latches (308). Upper side (302) and underside (304) are eachgenerally flat in the present example, though it should be understoodthat upper side (302) and/or underside (304) may include various kindsof features as described elsewhere herein. Tongue (306) is configured toprovide a grip for an operator, thereby facilitating grasping andhandling of retainer (300) during use. Latches (308) are configured toreleasably secure retainer (300) to lower jaw (50) of end effector (40)as will be described in greater detail below. By way of example only,retainer (300) may be formed of molded plastic. Alternatively, retainer(300) may be formed using any other suitable material(s) ortechnique(s).

In the present example, buttress (200) is secured to underside (304) ofretainer (300), such that upper side (202) of buttress (200) apposesunderside (304) of retainer (300). In some versions, an adhesive such asupper adhesive layer (104) provides releasable adhesion of buttress(200) to underside (304) of retainer (300). In some other versions,retainer (300) includes one or more features (e.g., flanges, clips,etc.) that are configured to selectively retain buttress (200) againstunderside (304) of retainer (300). Various suitable ways in whichbuttress (200) may be releasably secured to underside (304) of retainer(300) will be apparent to those of ordinary skill in the art in view ofthe teachings herein.

As shown in FIG. 12A, the assembly formed by buttress (200) and retainer(300) may be placed before end effector (40) with anvil (60) in the openposition. In some instances, a peel-away film (not shown) is positionedover underside (204) of buttress (200) to protect buttress (200) and/orany adhesive material on underside (204) of buttress (200). In suchversions, the film is peeled away to expose underside (204) of buttress(200) before reaching the stage shown in FIG. 12A. Such a film maycomprise polytetrafluoroethylene (PTFE) and/or any other suitablematerial(s). After reaching the stage shown in FIG. 12A, the assemblyformed by buttress (200) and retainer (300) may then be placed on staplecartridge (70) such that underside (204) of buttress (200) apposinglycontacts deck (73) of staple cartridge (70); and such that latches (308)are releasably secured to lower jaw (50) as shown in FIG. 12B. Theoperator may then drive anvil (60) toward the closed position as shownin FIG. 12C, eventually compressing buttress (200) against deck (73) ofstaple cartridge (70). Such compression may promote adhesion betweenunderside (204) of buttress (200) and deck (73) of staple cartridge(70). After anvil (60) has been used to compress buttress (200) againstdeck (73) of staple cartridge (70), anvil (60) may be moved back to theopen position as shown in FIG. 12D. As also shown in FIG. 12D, retainer(300) may then be pulled away from end effector (40), leaving behindbuttress (200) adhered to deck (73) of staple cartridge (70). Upper side(202) of buttress (200) is exposed. End effector (40) is thus loadedwith buttress (200) and ready for use in severing and stapling tissue(90).

FIGS. 13A-13C show an end effector (40) loaded with buttress (200) beingused to drive a staple (77) through tissue (90). In FIG. 13A, tissue(90) is placed between anvil (60) and staple cartridge (70), abovebuttress (200), with anvil (60) in the open position. In FIG. 13B, anvil(60) is driven to the closed position, compressing tissue (90) againstbuttress (200) and staple cartridge (70). End effector (40) is thenactuated as described above, driving staple (77) through buttress (200)and tissue (90). As shown in FIG. 13C, crown (210) of driven staple (77)captures and retains buttress (200) against layer (94) of tissue (90).It should be understood that a series of staples (77) will similarlycapture and retain buttress (200) against layer (94) of tissue (90),thereby securing buttress (200) to tissue (90) as shown in FIG. 14 . Asend effector (40) is pulled away from tissue (90) after deployingstaples (77) and buttress (200), buttress (200) disengages deck (73) ofstaple cartridge (70), such that buttress (200) remains secured totissue (90) with staples (77). Buttress (200) thus provides structuralreinforcement to the lines of staples (77). As can also be seen in FIG.14 , knife member (80) also cuts through a centerline of buttress (200),separating buttress (200) into two sections (230, 240), such that eachsection (230, 240) remains secured to a respective severed region oftissue (90).

C. Exemplary Instrument and Technique for Securing Buttress to Anvil ofEnd Effector

FIGS. 15-17B show a combination of an exemplary buttress (400) withretainer (300). Buttress (400) of this example may be constructed inaccordance with the teachings above relating to buttress assembly (100)and/or in accordance with other teachings herein. Buttress (400)includes an upper side (402) and an underside (404). In the presentexample, upper side (402) includes an adhesive (e.g., like upperadhesive layer (1064) to secure buttress (200) to underside (65) ofanvil (60) as described in greater detail below.

In the present example, buttress (400) is secured to upper side (302) ofretainer (300), such that underside (404) of buttress (400) apposesupper side (302) of retainer (300). In some versions, an adhesive suchas lower adhesive layer (106) provides releasable adhesion of buttress(400) to upper side (302) of retainer (300). In some other versions,retainer (300) includes one or more features (e.g., flanges, clips,etc.) that are configured to selectively retain buttress (400) againstupper side (302) of retainer (300). Various suitable ways in whichbuttress (200) may be releasably secured to upper side (302) of retainer(300) will be apparent to those of ordinary skill in the art in view ofthe teachings herein.

As shown in FIG. 17A, the assembly formed by buttress (400) and retainer(300) may be placed before end effector (40) with anvil (60) in the openposition. In some instances, a peel-away film (not shown) is positionedover upper side (402) of buttress (400) to protect buttress (400) and/orany adhesive material on upper side (402) of buttress (400). In suchversions, the film is peeled away to expose upper side (402) of buttress(400) before reaching the stage shown in FIG. 17A. Such a film maycomprise polytetrafluoroethylene (PTFE) and/or any other suitablematerial(s). After reaching the stage shown in FIG. 17A, the assemblyformed by buttress (400) and retainer (300) may then be placed on staplecartridge (70) such that latches (308) are releasably secured to lowerjaw (50) as described above. The operator may then drive anvil (60)toward the closed position as described above, eventually compressingbuttress (400) underside (65) of anvil (60). Such compression maypromote adhesion between upper side (402) of buttress (400) andunderside (65) of anvil (60). After anvil (60) has been used to compressbuttress (200) against underside (65) of anvil (60), anvil (60) may bemoved back to the open position as shown in FIG. 17B. As also shown inFIG. 17B, retainer (300) may then be pulled away from end effector (40),leaving behind buttress (400) adhered to underside (65) of anvil (60).Underside (402) of buttress (400) is exposed. End effector (40) is thusloaded with buttress (400) and ready for use in severing and staplingtissue (90).

FIGS. 18A-18C show an end effector (40) loaded with buttress (400) beingused to drive a staple (77) through tissue (90). In FIG. 18A, tissue(90) is placed between anvil (60) and staple cartridge (70), belowbuttress (400), with anvil (60) in the open position. In FIG. 18B, anvil(60) is driven to the closed position, compressing tissue (90) againstbuttress (400) and staple cartridge (70). End effector (40) is thenactuated as described above, driving staple (77) through buttress (400)and tissue (90). As shown in FIG. 18C, bent legs (220) of driven staple(77) capture and retains buttress (400) against layer (92) of tissue(90). It should be understood that a series of staples (77) willsimilarly capture and retain buttress (400) against layer (92) of tissue(90), thereby securing buttress (400) to tissue (90) as shown in FIG. 19. As anvil (60) is returned to the open position to enable end effector(40) to be pulled away from tissue (90) after deploying staples (77) andbuttress (400), buttress (400) disengages underside (65) of anvil (60),such that buttress (400) remains secured to tissue (90) with staples(77). Buttress (400) thus provides structural reinforcement to the linesof staples (77). As can also be seen in FIG. 19 , knife member (80) alsocuts through a centerline of buttress (400), separating buttress (400)into two sections (430, 440), such that each section (430, 440) remainssecured to a respective severed region of tissue (90).

While the examples above provide either buttress (200) on underside(304) of retainer (300) or buttress (400) on upper side (302) ofretainer (300), it should be understood that both retainers (200, 400)may be provided on the same retainer (300) if desired. In particular,retainer (200) may be provided on underside (304) of retainer (300)while buttress (400) is provided on upper side (302) of retainer (300).This may result in buttress (200) being provided on deck (73) of staplecartridge (70) and buttress (400) being provided on underside (65) ofanvil (60) in the same end effector (400). This may ultimately result inbuttress (200) being secured against layer (94) of tissue (90) by crowns(210) of staples (77) while buttress (400) is secured against layer (92)of tissue (90) by bent legs (220) of the same staples (77).

III. Exemplary Materials and Techniques for Providing Adhesion ofButtress to Surgical Stapler

As noted above, a buttress assembly (100) may include at least one layer(104, 106) of adhesive material (or other form of adhesive material)that adheres buttress body (102) to either underside (65) of anvil (60)or deck (73) of staple cartridge (70). Such an adhesive material mayprovide proper positioning of buttress body (102) before and duringactuation of end effector (40); then allow buttress body (102) toseparate from end effector (40) after end effector (40) has beenactuated, without causing damage to buttress body (102) that issubstantial enough to compromise the proper subsequent functioning ofbuttress body (102). It may be desirable to minimize the impact of suchan adhesive material on the functioning of firing beam (82) wedge sled(78), and staple drivers (75). For instance, it may be desirable toprevent the adhesive material from blocking or otherwise providingsignificant resistance to movement of firing beam (82) wedge sled (78),and staple drivers (75). Moreover, the adhesive material should allowbuttress body (102) to detach easily enough from an actuated endeffector (40) to avoid tearing tissue (90) after staples (77) have beenfired through the tissue and anvil (60) is moved to the open position.

In some instances, it may be desirable for the adhesive material toprovide additional effects, beyond merely adhering buttress body (102)to either underside (65) of anvil (60) or deck (73) of staple cartridge(70). For instance, the adhesive material may include one or morecomponents that provide a therapeutic effect, hemostatic effect, orother desired effect on tissue (90). As another merely illustrativeexample, the adhesive material may fill in at least part of the pathsthat are formed through tissue (90) and/or buttress body (102) by legs(220) of staple (77) being driven through tissue (90) and buttress body(102).

In some instances, the adhesive material for a buttress body (102) maybe pressure sensitive. In addition or in the alternative, the adhesivematerial may be configured to take the form of surface irregularities ofbuttress body (102); in addition to or in lieu of taking the form ofsurface irregularities in underside (65) of anvil (60) and/or deck (73)of staple cartridge (70).

The above noted characteristics of an adhesive material for a buttressbody (102) are merely illustrative examples. Suitable adhesive materialsmay possess various other characteristics in addition to or in lieu ofthose above. Suitable adhesive materials may also be provided in variousdifferent kinds of compositions. Examples of various suitablecompositions and configurations that may be used to form and provide anadhesive material for a buttress body (102), as well as variousexemplary characteristics that such adhesive material may possess, aredescribed in greater detail below.

A. Exemplary Polymeric Adhesive Materials with Synthetic Base

In some instances, an adhesive material (e.g., one or more of layers(104, 106)) for a buttress body (102) comprises an absorbable syntheticbased polymer. Various physiomechanical properties of synthetic basedpolymers may be modified in order to provide different adhesiveproperties. Such variable characteristics include but are not limited tocopolymer composition, glass transition temperature (Tg), molecularweight, inherent viscosity (IV), crystallinity, sequence distribution,copolymer chain composition, melting temperature (Tm), and surfacetension. Several exemplary combinations of these variables will beprovided below, though it should be understood that these examples aremerely illustrative. It should also be understood that these examples ofadhesive materials may be provided in upper adhesive layer (104). Inaddition or in the alternative, these examples of adhesive materials maybe provided in lower adhesive layer (106). In addition or in thealternative, these examples of adhesive materials may be otherwiseintegrated into buttress body (102). It should therefore be understoodthat the adhesive material need not necessarily constitute a separatelayer that is discretely identifiable as being different from a layerdefined by buttress body (102).

In some examples, the adhesive material is formed by a copolymer oflactide and caprolactone (PLA/PCL). This composition may be provided ata ratio in the range of 20/80 to 60/40; or more particularly the rangeof 35/65 to 50/50. This composition may have a glass transitiontemperature (Tg) that is below 4° C., or more particularly below −10° C.This composition may have a molecular weight in the range of 10,000g/mol to 145,000 g/mol; or more particularly below 200,000 g/mol. Thecomposition may have an inherent viscosity (IV) in the range of 1.0 dL/gto 2.0 dL/g.

In some other examples, the adhesive material is formed by a copolymerof lactide and trimethylene carbonate (PLA/TMC). This composition may beprovided at a ratio in the range of 20/80 to 50/50. The othercharacteristics may be within the same parameters set forth above withrespect to the exemplary PLA/PCL composition. Alternatively, the PLA/TMCcomposition may have any other suitable characteristics.

In some other examples, the adhesive material is formed by a copolymerof trimethylene carbonate and caprolactone (TMC/PCL). This compositionmay be provided at a ratio in the range of 20/80 to 80/20; or moreparticularly in the range of 50/50 to 60/40. This composition may havean inherent viscosity (IV) in the range of 0.3 dL/g to 3.0 dL/g; or moreparticularly in the range of 0.5 dL/g to 1.0 dL/g. This composition mayhave a crystallinity below 20%; or more particularly below 5%; or moreparticularly at 0% (i.e., a completely amorphous polymer). Thiscomposition may have a glass transition temperature (Tg) below 0° C.; ormore particularly below −20° C.

In some other examples, the adhesive material is formed by a copolymerof caprolactone and glycolide (PCL/PGA). This composition may beprovided at a ratio in the range of 45/55 to 85/15; or more particularlyin the range of 40/60 to 65/35; or more particularly in the range of50/50 to 65/35. This composition may have an inherent viscosity (IV) inthe range of 0.2 dL/g to 3.0 dL/g; or more particularly in the range of1.0 dL/g to 2.0 dL/g. This composition may have a molecular weight inthe range of 100,000 g/mol to 200,000 g/mol. This composition may have acrystallinity below 20%; or more particularly below 5%; or moreparticularly at 0% (i.e., a completely amorphous polymer). Thiscomposition may have a glass transition temperature (Tg) below 0° C.; ormore particularly below −20° C. One particular example of thiscomposition has a ratio of 50/50 PCL/PGA; an inherent viscosity (IV) of0.2; a molecular weight of 83,000 g/mol; and a glass transitiontemperature (Tg) of −19.4°. Another particular example of thiscomposition has a ratio of 65/35 PCL/PGA; an inherent viscosity (IV) of1.04 to 1.07; a molecular weight of 110,000 g/mol to 118,000 g/mol; anda glass transition temperature (Tg) in the range of −37.3° to −38.6°.

Other exemplary synthetic based polymer compositions that may be used toform the adhesive material include the following: propanediol andcaprolactone (PDO/PCL); a combination of propanediol, caprolactone, andtrimethylene carbonate (PDO/PCL/TMC), with very low to no crystallinityand a glass transition temperature (Tg) below 0° C.; and a homopolymerpoly(TMC), with an inherent viscosity (IV) of approximately 0.5 dL/g.Other suitable synthetic based polymer compositions will be apparent tothose of ordinary skill in the art in view of the teachings herein.

The adhesive material may include a blocky copolymer. For instance, oneexample of a blocky copolymer that may be used in the adhesive materialcomprises blocky poly(TMC), with a low glass transition temperature(Tg). In some instances, the blocky copolymer may be randomized. In someother instances, such as when the copolymer is amorphous (e.g., 0%crystallinity), the blocky copolymer may be ordered.

The adhesive material may include various kinds of copolymer chaincompositions. For instance, the copolymer chain composition may bebranched with relatively short segments. This may further enhance themalleability experience. Alternatively, the copolymer chain may belinear. As another alternative, the copolymer may be cross-linked orstar pattern. However, in versions where the copolymer is cross-linked,it may be desirable for the base copolymer segments to be more amorphousthe more that those segment are cross-linked.

As noted above, the melting temperature (Tm) is a physiomechanicalproperty of a polymer that may be selected to provide desired adhesivecharacteristics. In some instances, the lower melting temperature (Tm)of a monomer component could limit the amount of the co-monomer neededto create a desired adhesive effect. By way of example only,polydioxanone (PDS) has a melting temperature (Tm) around approximately110° C. and a glass transition temperature (Tg) around approximately−10° C. Thus, polydioxanone (PDS) may need less caprolactone (PCL) tomake a suitable pressure sensitive adhesive (PSA) copolymer. It shouldalso be understood that polydioxanone (PDS) copolymers withpolyglycolide (PGA) or lactide (PLA) may provide desired adhesiveeffects. It may be desirable for such copolymers to have a glasstransition temperature (Tg) that is below room temperature; a meltingtemperature (Tm) that is at or below room temperature; a crystallinityin the range of 10% to 0%; and an inherent viscosity (IV) that is lessthan 2.0 dL/g, or more particularly less than 1.0 dL/g.

In some examples the adhesive material may comprise a blended copolymer.For instance, the high and low molecular weight of the same pressuresensitive adhesive (PSA) copolymer may allow for the degradation rate tobe adjusted without adjusting the polymer chemistry. As the lowmolecular weight version breaks down, its acid byproducts would thenchange the pH and effect the breakdown of the high molecular weightparts. Preferred blends of copolymers would include those that will notaffect the crystallinity, low melting temperature (Tm), and low glasstransition temperature (Tg) of the copolymers.

Some examples of the adhesive material may comprise polyurethane. Forinstance, the polyurethane may be provided as a pressure sensitiveadhesive (PSA). By of example only, polyurethane based pressuresensitive adhesives (PSAs) may be prepared from isocyanates, polyols,and chain extenders. Pressure sensitive adhesives (PSAs) may also beprepared from 100% solids, waterborne, or solvent borne systems. Theproperties of polyurethane based pressure sensitive adhesives (PSAs) maybe controlled by varying the ratio of isocyanates to polyols and chainextenders. As another merely illustrative example, the polyurethane maybe provided in a flowable form. For instance, a flowable polyurethanebased adhesive material may have an inherent viscosity (IV) that is lessthan 1.0 dL/g, or more particularly less than 0.5 dL/g; a glasstransition temperature (Tg) that is in the range of −10° C. and 10° C.;or more particularly closer to −10° C.; and a consistency similar tothat of honey or oil, if desired, with the proper inherent viscosity(IV).

The foregoing examples of absorbable synthetic based polymers areprovided for merely illustrative purposes. Other suitable examples willbe apparent to those of ordinary skill in the art in view of theteachings herein. It should also be understood that the foregoingexamples of absorbable synthetic based polymers may be readilyincorporated into the various teachings and examples provided below. Inother words, the foregoing examples of absorbable synthetic basedpolymers may be readily incorporated into any example herein that refersto an adhesive material.

B. Exemplary Polymeric Adhesive Materials with Natural Base

While the above discussion provides various examples of synthetic basedpolymers that may be used as an adhesive material (e.g., one or more oflayers (104, 106)) for a buttress body (102), it should also beunderstood that a natural based polymer may be used as an adhesivematerial. Several merely illustrative examples of natural based polymersthat may be used as an adhesive material will be described in greaterdetail below. It should also be understood that these examples ofadhesive materials may be provided in upper adhesive layer (104). Inaddition or in the alternative, these examples of adhesive materials maybe provided in lower adhesive layer (106). In addition or in thealternative, these examples of adhesive materials may be otherwiseintegrated into buttress body (102). It should therefore be understoodthat the adhesive material need not necessarily constitute a separatelayer that is discretely identifiable as being different from a layerdefined by buttress body (102).

In some instances, the adhesive material comprises a hydrogel. Thehydrogel may generally comprise a hydrophilic polymer network capable ofabsorbing and/or retaining fluids. An exemplary hydrogel material isglycol methacrylate. By way of further example only, suitable hydrogelmaterials may comprise homopolymer hydrogels, copolymer hydrogels,multipolymer hydrogels, interpenetrating polymer hydrogels, andcombinations thereof. In further examples, the hydrogel may comprisemicrogels, nanogels, and combinations thereof. The hydrogel may furthercomprise a non-crosslinked hydrogel, a crosslinked hydrogel, andcombinations thereof. The hydrogel may comprise chemical crosslinks,physical crosslinks, hydrophobic segments and/or water insolublesegments. The hydrogel may be chemically crosslinked by polymerization,small-molecule crosslinking, and/or polymer-polymer crosslinking. Thehydrogel may be physically crosslinked by ionic interactions,hydrophobic interactions, hydrogen bonding interactions,sterocomplexation, and/or supramolecular chemistry. The hydrogel may besubstantially insoluble due to the crosslinks, hydrophobic segmentsand/or water insoluble segments, but be expandable and/or swellable dueto absorbing and/or retaining fluids. In some versions, the precursormay crosslink with endogenous materials and/or tissues.

Further examples of hydrogels that may be used include multifunctionalacrylates, hydroxyethylmethacrylate (HEMA), and elastomeric acrylates.In additional or in the alternative, a hydrogel adhesive material may beconstructed in accordance with at least some of the teachings of U.S.Pat. Pub. No. 2012/0241492, entitled “Tissue Thickness CompensatorComprising at Least One Medicament,” published Sep. 27, 2012, issued asU.S. Pat. No. 9,839,420 on Dec. 12, 2017, the disclosure of which isincorporated by reference herein. Other suitable ways in which anadhesive material may be provided with hydrogel will be apparent tothose of ordinary skill in the art in view of the teachings herein.

Further examples of naturally based polymers that may be used to form anadhesive material include alginate (e.g., calcium alginate, calciumsodium alginate, etc.); hyaluronic acid, collagen (including gelatin),and polysaccharide. In versions including a polysaccharide, thepolysaccharide may include cellulose, chitin, pectin, or arabinoxylans.In versions including cellulose, the cellulose may comprise oxidizedregenerated cellulose, carboxy-methylcellulose, carboxyethyl cellulose,hydroxypropyl cellulose, hydroxyethyl cellulose, or oxidized cellulose.In versions including chitin, the chitin may comprise chitosan (e.g.,deacetylated chitin) or chitosan salts.

Some versions of naturally based polymers that may be used to form anadhesive material may include a putty or wax-like material. Some suchversions may be non-absorbable and may be similar to a conventional bonewax. For instance, the material may comprise beeswax with one or more ofthe paraffin, petroleum jelly, isopropyl palmitate, sesame oil, carbolicacid; or any other conventional bone wax composition. Some otherversions of a putty or wax-like material that may be used to form anadhesive material for buttress body (102) may be absorbable orresorbable. For instance, some such versions may comprise HEMASORB®putty by Abyrx, Ink of Irvington, N.Y., water-soluble alkylenecopolymers (e.g., OSTENE by Baxter Healthcare Corporation of Deerfield,Ill.), glycerol, 1-lactide, glycolide, polyethylene glycol (PEG),polyethylene oxide (PEO), or polyolefin elastomer (POE). By way offurther example, the adhesive material may comprise polyethylene glycol(PEG) or a polyethylene glycol (PEG) copolymer with a molecular weightof less than 20,000 g/mol. Having the molecular weight in such a rangemay promote passage of the dissolved form of the adhesive through thekidneys. See, e.g., Webster et al., “PEGylated Proteins: Evaluation ofTheir Safety in the Absence of Definitive Metabolism Studies,” DrugMetabolism and Disposition, Vol. 35, No. 1, pp. 9-16 (2007), thedisclosure of which is incorporated by reference herein. As yet anothermerely illustrative example, the adhesive material may be constructed inaccordance with at least some of the teachings of U.S. Pat. No.2,642,375, entitled “Hemostatic Compositions,” issued Jun. 16, 1953, thedisclosure of which is incorporated by reference herein.

Some polymer adhesives, including but not limited to the putty orwax-like compositions referred to above, may include oxidizedregenerated cellulose (ORC), which is a hemostatic agent. For instance,a putty or wax-like composition may serve as a carrier for oxidizedregenerated cellulose (ORC). U.S. Patent Pub. No. 2012/0241493, entitled“Tissue Thickness Compensator Comprising Controlled Release andExpansion,” published Sep. 27, 2012, issued as U.S. Pat. No. 10,123,798on Nov. 13, 2018, the disclosure of which is incorporated by referenceherein, discusses various ways in which oxidized regenerated cellulose(ORC) may be incorporated into various compositions. It should beunderstood that such teachings of U.S. Patent Pub. No. 2012/0241493,issued as U.S. Pat. No. 10,123,798 on Nov. 13, 2018, may be readilyapplied herein in the context of incorporating oxidized regeneratedcellulose (ORC) into polymer adhesives, including but not limited to theputty or wax-like compositions referred to above.

The foregoing examples of natural based polymers are provided for merelyillustrative purposes. Other suitable examples will be apparent to thoseof ordinary skill in the art in view of the teachings herein. It shouldalso be understood that the foregoing examples of natural based polymersmay be readily incorporated into the various teachings and examplesprovided below. In other words, the foregoing examples of natural basedpolymers may be readily incorporated into any example herein that refersto an adhesive material.

C. Exemplary Malleable Bioabsorbable Polymer Adhesive

In some instances, it may be desirable to provide one or more adhesivelayers (104, 106) with a malleable bioabsorbable polymer adhesive. Sucha polymer may be highly viscous yet still flowable at room temperature.A malleable polymer adhesive may, in response to pressure being appliedto it, take the form of a surface with which it is engaged. In otherwords, if a malleable polymer adhesive is pressed against deck (73) ofstaple cartridge (70), the malleable polymer adhesive may take the formof the one or more features of the deck (73) that it the malleablepolymer adhesive is pressed against. Similarly, if a malleable polymeradhesive is pressed against underside (65) of anvil (60), the malleablepolymer adhesive may take the form of the one or more features ofunderside (65) that it the malleable polymer adhesive is pressedagainst. By deforming to the geometry that it is pressed against, themalleable polymer adhesive may adhere to the geometry; and may furtherprovide re-applyable attachment. If the desired positioning of buttressassembly (100) on deck (73) or underside (65) is not achieved, themalleable polymer adhesive may permit buttress assembly (100) to beremoved, repositioned, and re-adhered to deck (73) or underside (65). Itshould be understood that the examples provided below may be malleableat room temperature, such that additional heating or other treatment isnot necessary in order to provide malleability.

Providing the adhesive material in the form of a malleable polymer mayminimize the impact of fluids and debris on the adhesion of buttressassembly (100) to deck (73) of staple cartridge (70) or underside (65)of anvil (60). The malleable polymer adhesive material may also behydrophilic (e.g., at least in certain regions of buttress assembly(100)), encouraging adhesion in a wet environment. In addition or in thealternative, adhesive layer (104, 102) of buttress assembly (100) mayinclude a combination of adhesive material and hydrophobic material inrespective localized regions. The hydrophobic material may drive fluidsout of the adhesion areas, thereby improving adhesion at the localizedregions of adhesive material.

In some instances, when a buttress assembly (100) having a malleablebioabsorbable polymer adhesive is sterilized using ethylene oxide at ahigh temperature, the ethylene oxide gas may act as a plasticizer,increasing the fluidic aspects of the adhesive. Buttress assembly (100)may include features that are configured to contain the adhesive at thisstage (and/or at other stages where the adhesive may become morefluidic), to maintain the adhesive properties of the adhesive later inits life cycle. For instance, such containment features may be providedby buttress body (102). In addition or in the alternative, suchcontainment features may be provided by a peel away film layer that isprovided on the opposite side of adhesive layer (104, 106), such thatthe adhesive layer (104, 106) is interposed between buttress body (102)and the peel away film layer. Such a peel away film layer may compriserecesses or cavities, etc., as features that provide a predefined spacewhere the viscous fluid adhesive may be retained. Other suitable formsof adhesive retention features will be apparent to those of ordinaryskill in the art in view of the teachings herein.

The below examples include various compositions of malleablebioabsorbable polymer adhesives and various exemplary configurationsthrough which a malleable bioabsorbable polymer adhesive may be combinedwith a buttress body (102). In the present example, it is contemplatedthat the adhesive material comprises a synthetic based polymer such asthose referred to herein. However, it should also be understood thatnaturally based polymers may be incorporated with the below teachings.It should also be understood that, even if some of the below examplesare provided specifically in the context of being applied to just deck(73) of staple cartridge (70), the same examples may be readily appliedto underside (65) of anvil (60). Similarly, to the extent that some ofthe below examples are provided specifically in the context of beingapplied to just underside (65) of anvil (60), the same examples may bereadily applied to deck (73) of staple cartridge (70).

1 Exemplary Compositions Providing Malleable Absorbable Polymer Adhesive

In some versions, the polymer adhesive is provided in a thin layerhaving properties in the range of malleable to flowable (highviscosity), with a tacky surface contact. In some versions, such polymeradhesives have a low inherent viscosity (IV) with low crystallinity. Onesuch composition may comprise a 65/35 copolymer of caprolactone andglycolide (PCL/PGA). Another such composition may comprise a 65/35copolymer of trimethylene carbonate and caprolactone (TMC/PCL). Anothersuch composition may comprise a 75/25 copolymer of lactide andcaprolactone (PLA/PCL). Another such composition may comprise acopolymer of trimethylene carbonate and lactide (TMC/PLA).

It should also be understood that some of the putty or wax-likecompositions previously referred to may be used to provide a malleablepolymer adhesive. Absorbable versions of such compositions includeHEMASORB® putty by Abyrx, Ink of Irvington, N.Y., water-soluble alkylenecopolymers (e.g., OSTENE by Baxter Healthcare Corporation of Deerfield,Ill.), glycerol, 1-lactide, glycolide, and polyethylene glycol (PEG).Non-absorbable versions of such compositions include beeswax with one ormore of the paraffin, petroleum jelly, isopropyl palmitate, sesame oil,carbolic acid; or any other conventional bone wax composition. Somemalleable polymer adhesives, including but not limited to the putty orwax-like compositions, may include oxidized regenerated cellulose (ORC),as further noted above.

The foregoing are just a few merely illustrative examples of malleablepolymer compositions that may be used to adhere buttress body (102) tounderside (65) of anvil (60) or deck (73) of staple cartridge (70). Byway of further example only, other suitable compositions may includevarious other compositions referred to herein and variations thereof.

2. Exemplary Structural Configurations Incorporating a MalleableAbsorbable Polymer Adhesive with a Buttress

There are a variety of structural configurations that may be used toincorporate a malleable absorbable polymer adhesive with a buttress body(102) to form a buttress assembly (100) that may be adhered to underside(65) of anvil (60) or deck (73) of staple cartridge (70). Several merelyillustrative examples are described in greater detail below. Furtherexamples will be apparent to those of ordinary skill in the art in viewof the teachings herein. It should also be understood that, while thefollowing examples are provided as separate examples, the concepts andfeatures of the following examples may be combined with each other innumerous ways as will be apparent to those of ordinary skill in the artin view of the teachings herein.

a. Thin Film Malleable Polymer Adhesive on Buttress

A malleable absorbable polymer adhesive may be provided as a thin filmon buttress body (102). In one merely illustrative example, a copolymeradhesive film layer (104, 106) is compression molded in a 65/35caprolactone and glycolide (PCL/PGA) form to a thickness in the range of75 mils to 250 mils. The compressed adhesive film layer (104, 106) canthen be pressed into adhesive contact with buttress body (102). Apolytetrafluoroethylene (PTFE) film may be applied to the exposed faceof adhesive film layer (104, 106) to protect the face of adhesive filmlayer (104, 106). Right before the resulting buttress assembly (100) isto be applied to deck (73) of staple cartridge (70) or underside (65) ofanvil (60), the polytetrafluoroethylene (PTFE) film may be removed toexpose the adhesive film layer (104, 106). The exposed adhesive filmlayer (104, 106) may then be pressed against deck (73) of staplecartridge (70) or underside (65) of anvil (60), thereby adheringbuttress assembly (100) to deck (73) of staple cartridge (70) orunderside (65) of anvil (60).

In another merely illustrative example, a fluidic composition of 50/50caprolactone and glycolide (PCL/PGA) is heated and painted onto buttressbody (102), thereby providing a thin adhesive film layer (104, 106). Asthe film adhesive film layer (104, 106) cools to room temperature, theadhesive film layer (104, 106) behaves like a thick compressed filmelement to adhere to deck (73) of staple cartridge (70) or underside(65) of anvil (60). As described above, a polytetrafluoroethylene (PTFE)film may be used to selectively protect and expose the adhesive filmlayer (104, 106).

In versions where a malleable absorbable polymer adhesive is provided asa thin film on buttress body (102), it should be understood thatadhesion may occur as the thin adhesive film layer (104, 106) isdeformed due to compression against deck (73) of staple cartridge (70)or underside (65) of anvil (60). The adhesive film layer (104, 106) hasa tacky surface condition but the adhesion may actually be providedthrough a combination of cohesion, surface tension, deformation of thecontact surface to mate directly to the geometry of deck (73) of staplecartridge (70) or underside (65) of anvil (60), and some tacky adhesion,rather than just adhesion alone.

b. Openings Formed Through Malleable Polymer Adhesive Layer to LimitMigration

In some versions, buttress assembly (100) includes a geometry and/orother features that improve adhesion and/or prevent inadvertent flow ofadhesive material into undesirable regions. FIGS. 20-21 show anexemplary buttress assembly (500) that is configured to provide suchproperties. Buttress assembly (500) of this example comprises a buttressbody (502), an intermediate layer (510), and an adhesive layer (520).Buttress body (502) may be configured and operable just like buttressbody (102) described above. Adhesive layer (520) may comprise any of thevarious adhesive materials referred to herein, including but not limitedto any of the various absorbable malleable polymer compositions.

Intermediate layer (510) is interposed between buttress body (502) andadhesive layer (520). At least a portion of intermediate layer (510) maybe impermeable or semi impermeable as described above, to prevent orrestrict migration of adhesive material from adhesive layer (520) intobuttress body (502). Intermediate layer (510) is configured to promoteand prevent adhesion of the material forming adhesive layer (520) atdifferent regions. In particular, as best seen in FIG. 20 , in whichbuttress assembly (500) is applied to a deck (73) of a staple cartridge(70), adhesive layer (520) includes an opening (522) over each staplepocket (74) of staple cartridge (70). Openings (522) are configured toprevent the material forming adhesive layer (520) from entering orotherwise covering staple pockets (74), thereby preventing the adhesivelayer from inhibiting the exit of staples (77) from staple pockets (74).Adhesive layer (520) further includes an opening (524) in the form of alongitudinal channel over channel (72) of staple cartridge (70). Opening(524) is configured to prevent the material forming adhesive layer (520)from entering or otherwise covering channel (72), thereby preventing theadhesive layer from inhibiting the distal motion of firing beam (82)through channel (72). In instances where buttress assembly (500) isapplied to underside (65) of anvil (60), openings (522) may be sized andpositioned to prevent the material forming adhesive layer (520) fromentering or otherwise covering staple forming pockets (64). Similarly,opening (524) may be configured to prevent the material forming adhesivelayer (520) from entering or otherwise covering channel (62).

In the present example, openings (522, 524) are formed due to thepresence of features of intermediate layer (510) that are configured toprevent adhesion of the adhesive material. In other words, when theadhesive material is applied to intermediate layer during the process offorming adhesive assembly (500), those features of intermediate layerkeep the adhesive material away from the regions where openings (522,524) are intended to be formed. By way of example only, such featuresmay comprise a micro and/or macro surface finish features and/or otherkinds of features. As another merely illustrative example, intermediatelayer (510) may comprise macro standing features that keep the adhesivematerial away from the regions where openings (522, 524) are intended tobe formed. As yet another merely illustrative example, a die or otherdevice may be used to keep the adhesive material away from the regionswhere openings (522, 524) are intended to be formed. Such a die may beremoved at any suitable time before buttress assembly (500) is appliedto deck (73) of staple cartridge (70) or underside (65) of anvil (60).Other suitable ways in which openings (522, 524) may be formed will beapparent to those of ordinary skill in the art in view of the teachingsherein. It should also be understood that intermediate layer (510) mayinclude a surface finish and/or other surface features that is/areconfigured to promote adhesion of the adhesive material to the regionsoutside of openings (522, 524).

FIG. 21 shows an example of a set of staples (77) driven through tissue(90), with two buttress assemblies (500) secured to the tissue (90). Inthis example, one buttress assembly (500) had been secured to deck (73)of staple cartridge (70) while another buttress assembly (500) had beensecured to underside (65) of anvil (60). As can be seen, openings (522)are sized to accommodate staples (77) at each buttress assembly (500).Thus, neither crowns (210) nor legs (220) of staples (77) have passedthrough any of the material forming adhesive layer (520) in eitherbuttress assembly (500).

c. Malleable Polymer Adhesive Rods

FIGS. 22A-22B show an exemplary buttress assembly (600) comprising abuttress body (602) and a set of adhesive rods (620). Buttress body(602) may be configured and operable just like buttress body (102)described above. Adhesive rods (620) may comprise any of the variousadhesive materials referred to herein, including but not limited to anyof the various absorbable malleable polymer compositions. By way ofspecific example only, adhesive layer (620) may comprise one of theputty or wax-like compositions previously referred to.

Buttress assembly (600) is shown as being used in combination with astaple cartridge (670) that is substantially similar to staple cartridge(70). However, staple cartridge (670) of this example comprises upwardlyextending, U-shaped lip members (680) around the end of each staplepocket (674). Staple cartridge (670) is otherwise identical to staplecartridge (70).

Adhesive rods (620) are oriented to extend longitudinally, such thatadhesive rods are parallel to each other and parallel to thelongitudinal axis defined by staple cartridges (70). Adhesive rods (620)are positioned laterally between lip members (680), such that lipmembers (680) are configured to maintain the positioning of adhesiverods (620). During an initial stage of applying buttress assembly (600)as shown in FIG. 22A, to deck (674) of staple cartridge (670), adhesiverods (620) are cylindrical in form, each having a substantially circularcross section. Buttress body (602) is then pressed against adhesive rods(520), causing adhesive rods (620) to malleably deform as shown in FIG.22B. This malleable deformation adheres buttress body (602) to deck(674) of staple cartridge (670). Lip members (680) prevent the materialforming adhesive rods (620) from entering or otherwise blocking staplepockets (674) during and after this deformation of adhesive rods (620).With buttress body (602) secured to deck (674) of staple cartridge (670)by malleably deformed adhesive rods (620), the end effector that isequipped with staple cartridge (670) and buttress assembly (600) isready for use as described herein. It should be understood that, withlip members (680) shielding staple pockets (674) from the adhesivematerial forming adhesive rods (620), the staples driven from staplecartridge (670) will not pass through the adhesive material when staplecartridge (670) is actuated. It should also be understood that adhesiverods (620) (or adhesive structures that are similar to adhesive rods(620) may be positioned on underside (65) of anvil (60) to secure abuttress body (602) to underside (65) of anvil (60). Such adhesive rods(620) may be laterally positioned between longitudinally extending rowsof staple forming pockets (64).

d. Discrete Regions of Malleable Polymer Adhesive with Retainer HavingAdhesive Driving Features

FIG. 23 shows an exemplary alternative buttress assembly (700) with anexemplary alternative retainer (750). Buttress assembly (700) of thisexample comprises a buttress body (702) and a plurality of discretelyformed adhesive regions (720). Buttress body (702) may be configured andoperable just like buttress body (102) described above. Adhesive regions(720) may comprise any of the various adhesive materials referred toherein, including but not limited to any of the various absorbablemalleable polymer compositions. In the present example, adhesive regions(720) are square shaped, though it should be understood that adhesiveregions (720) may have any other suitable configuration.

Retainer (750) comprises a base member (752) having an upper surface(754), a plurality of latches (756), and a distally projecting tongue(758) that is configured to facilitate grasping and manipulation ofretainer (750). Retainer (750) also includes an upper member (760) thatis secured to base member (752) by a living hinge (770). Upper member(760) has an upper surface (762) that is configured to engage buttressbody (702). A plurality of openings (764) are formed through uppermember (760). Openings (764) are configured and arranged to correspondwith the configuration and arrangement of adhesive regions (720) whenbuttress assembly (700) is laid over upper surface (762). A plurality ofrigid posts (766) extend upwardly from upper surface (754) of basemember (752). Posts (766) are configured and arranged to correspond withthe configuration and arrangement of openings (764) and adhesive regions(720).

It should be understood that retainer (750) may be removably secured toend effector (40) in a manner similar to retainer (300) described above,with latches (756) releasably engaging lower jaw (50). At such a stage,upper member (760) is spaced away from upper surface (754) of basemember (752) due to a resilient bias imposed by living hinge (770).Retainer (750) may thus be configured as shown in FIG. 24A, where anvil(60) is brought into initial contact with buttress assembly (700). Asshown, an adhesive region (720) of buttress assembly (700) is positioneddirectly under a pair of staple forming pockets (64). Alternatively,adhesive region (720) may be positioned under some other feature ofunderside (65) of anvil (60). The resilient bias provided by livinghinge (770) ensures that adhesive region (720) contacts the appropriateregion of underside (65) of anvil (60) before anvil (60) reaches a fullyclosed position. The resilient bias provided by living hinge (770) mayalso provide and maintain a minimum consistent pressure during theclosure of anvil (60) to enhance the attachment of adhesive region (720)to underside (65) of anvil (60).

As anvil (60) is driven further toward the closed position, anvil (60)bears down on adhesive region (720) and upper member (760), therebycausing upper member (760) to pivot toward base member (752). As uppermember (760) pivots toward base member (752), post (764) passes throughopening (762). The height of post (764) is greater than the verticalthickness of upper member (760), such that the top of post (764)protrudes above upper surface (762) of upper member (760) when uppermember (760) is driven downwardly into apposition with upper surface(754) of base member (752). The protruding top of post (764) provides anopposing force against the underside of buttress body (702), in theregion beneath adhesive region (720). Adhesive region (720) is thuscompressed between underside (65) of anvil (60) and the region ofbuttress body (702) just above the top of post (764). This compressionresults in malleable deformation of adhesive region (720), such that thematerial forming adhesive region takes the form of the correspondingstaple forming pockets (64), as shown in FIG. 24B.

It should be understood that the foregoing actions may take place atevery post (764) and adhesive region (720), such that the adhesiveregions (720) together adhere buttress assembly (700) to underside (65)of anvil (60). At this stage, latches (768) of retainer (750) may secureupper member (760) into apposition with base member (752), facilitatingremoval of retainer (750) from end effector (40). Buttress assembly(700) is left adhered to underside (65) of anvil (60) as shown in FIG.24C, such that end effector (40) is then ready for use.

e. Buttress Assembly with Malleable Polymer Adhesive in AsymmetricGeometries and Thicknesses

FIG. 25 shows an exemplary buttress assembly (800) comprising a buttressbody (802) and a plurality of adhesive regions (820, 822, 824, 830).Buttress body (802) may be configured and operable just like buttressbody (102) described above. Adhesive regions (820, 822, 824, 830) maycomprise any of the various adhesive materials referred to herein,including but not limited to any of the various absorbable malleablepolymer compositions. A first adhesive region (820) extends laterallyalong a proximal portion of buttress body (802), spanning substantiallythe full width of buttress body (802). A second adhesive region (822) islocated near the longitudinal and lateral center of buttress body (802).Third and fourth adhesive regions (824) extend longitudinally along eachlateral side of buttress body (802). Fifth and sixth adhesive regions(830) are located at the distal end of buttress body (802), at thecorners. Each adhesive region (830) includes a thick portion (832) and athin portion (834). It should be understood that any of the otheradhesive regions (822, 824, 830) may also have thick and thin portions.In addition or in the alternative, some adhesive regions (820, 822, 824,830) may be thicker than other adhesive regions (820, 822, 824, 830). Inaddition or in the alternative, some adhesive regions (820, 822, 824,830) may have a greater density than other adhesive regions (820, 822,824, 830). Similarly, any one of the adhesive regions (820, 822, 824,830) may have varying intra-region density.

It should be understood that providing varying thicknesses and/ordensities among and/or within adhesive regions (820, 822, 824, 830) mayresult in a non-homogenous pressure distribution on adhesive regions(820, 822, 824, 830) when buttress assembly (800) is pressed againstdeck (73) of staple cartridge (70) or underside (65) of anvil (60). Suchnon-homogenous pressure distribution may maximize bonding in certainareas while letting other areas have less deformation and adhesion.Other suitable ways in which a buttress assembly may be formed withvarying thicknesses and/or densities among and/or within adhesiveregions will be apparent to those of ordinary skill in the art in viewof the teachings herein.

D. Low Inherent Viscosity Bioabsorbable Polymer Adhesive

In some instances, it may be desirable to provide one or more adhesivelayers (104, 106) with a bioabsorbable polymer adhesive having a lowinherent viscosity (IV). The below examples include various exemplaryconfigurations through which a bioabsorbable polymer adhesive having alow inherent viscosity (IV) may be combined with a buttress body (102).In the present example, it is contemplated that the adhesive materialcomprises a synthetic based polymer such as those referred to herein.However, it should also be understood that naturally based polymers maybe incorporated with the below teachings.

One example of a suitable adhesive copolymer having a low inherentviscosity (IV) is a 65/35 composition of caprolactone and glycolide(PCL/PGA) having low crystallinity, with an inherent viscosity (IV) inthe range of about 0.8 dL/g to about 1.0 dL/g. A 65/35 composition ofcaprolactone and glycolide (PCL/PGA) with a low inherent viscosity (IV)and having a molecular weight near or equal to that of Monocryl (whichhas a 75/25 composition of caprolactone and glycolide (PCL/PGA)) mayalso provide suitable adhesive properties. Another example of a suitableadhesive copolymer having a low inherent viscosity (IV) is a compositionof caprolactone and glycolide (PCL/PGA) with an inherent viscosity (IV)in the range of 0.2 dL/g to 1.0 dL/g. Another example of a suitableadhesive copolymer having a low inherent viscosity (IV) is a compositionof trimethylene carbonate and caprolactone (TMC/PCL) with an inherentviscosity (IV) in the range of 0.3 dL/g to 1.0 dL/g, or moreparticularly in the range of 0.5 dL/g to 1.0 dL/g. Another suitableadhesive having a low inherent viscosity (IV) is caprolactone (PCL) withan inherent viscosity (IV) in the range of 0.2 dL/g to 0.9 dL/g.

Inherent viscosity (IV) reflects a measurement of molecular size. It isbased on the flow time of a polymer solution through small capillarychannels over time. The inherent viscosity (IV) and molecular weight ofa polymer are related, but that relational agreement is different foreach copolymer composition. For instance, the correlation of inherentviscosity (IV) to molecular weight may be logarithmic with only a smallmidsection of the curve being linear. This logarithmic correlation maydiffer as the copolymer composition differs. It is not necessarilyrequired to have a low molecular weight copolymer in order to manifestadhesive and malleable properties. Low molecular weight copolymers mayalso have shortened degradation cycles and reduced structural strength.The ideal adhesion film or adhesive substrate to use in adhesive layer(104, 106) would have higher molecular weight and low inherent viscosity(IV) to be both strong and adhesive. By way of example only, a suitableadhesive material having a low inherent viscosity (IV) may have amolecular weight in the range of 11,000 g/mol to 30,000 g/mol. Themolecular weight may be higher in cases where the inherent viscosity(IV) is particularly low. For instance, a suitable adhesive material maycomprise a 50/50 composition of caprolactone and glycolide (PCL/PGA)with an inherent viscosity of about 0.2 dL/g and a molecular weight ofabout 83,000 g/mol.

E. Low Glass Transition Temperature Bioabsorbable Polymer Adhesive

In some instances, it may be desirable to provide one or more adhesivelayers (104, 106) with a bioabsorbable polymer adhesive having a lowglass transition temperature (Tg). The below examples include variousexemplary configurations through which a bioabsorbable polymer adhesivehaving a low glass transition temperature (Tg) may be combined with abuttress body (102). In the present example, it is contemplated that theadhesive material comprises a synthetic based polymer such as thosereferred to herein. However, it should also be understood that naturallybased polymers may be incorporated with the below teachings.

Glass transition temperature (Tg) is the temperature at which themechanical properties of a copolymer change dramatically from a flowableadhesive to a brittle plastic. The glass transition temperature (Tg) islower than the melting point of the crystalline form of the samecopolymer. The glass transition temperature (Tg) may be indicative ofhow the polymer behaves under ambient conditions. The meltingtemperature (Tm) may be referred to as the “first-order transition,”which is where the polymer changes state from solid to liquid.Crystalline polymers have a true melting point, which is the temperatureat which the crystallites melt and the total mass of plastic becomesamorphous. Amorphous polymers do not have a true melting point, but theydo have a first-order transition where their mechanical behaviortransitions from a rubbery nature to viscous rubbery flow. Suitablepolymers for use in forming adhesive layer (102, 104) may have a percentof crystallinity making them behave both amorphically and crystally. Theglass transition temperature (Tg) can be effected by composition,polymer chain configuration and stiffness, molecular weight, viscosity,shear modulus, heat capacity, thermal expansion, cross-linking and otherfactors. It is therefore possible to have a relatively low glasstransition temperature (Tg) material composition that does not alwayscorrespond to low molecular weight or low inherent viscosity (IV).

In versions where the adhesive material comprises a composition ofcaprolactone and glycolide (PCL/PGA), the glass transition temperature(Tg) may be below about 0° C., and more particularly below about −20° C.One specific example of a suitable adhesive copolymer having a low glasstransition temperature (Tg) is a 65/35 composition of caprolactone andglycolide (PCL/PGA), with a low inherent viscosity (IV) and lowcrystallinity, having a glass transition temperature (Tg) of less thanabout −35° C. Another specific example of a suitable adhesive copolymerhaving a low glass transition temperature (Tg) is a 50/50 composition ofcaprolactone and glycolide (PCL/PGA), with a low inherent viscosity (IV)and low crystallinity, having a glass transition temperature (Tg) ofless than about −19° C.

Another example of a suitable adhesive copolymer having a low glasstransition temperature (Tg) is a 50/50 composition of trimethylenecarbonate and caprolactone (TMC/PCL), with a low inherent viscosity (IV)and low crystallinity, having a glass transition temperature (Tg) belowabout 0° C. and more particularly below about −20° C. In versions wherethe adhesive material comprises a composition of lactide andcaprolactone (PLA/PCL), the glass transition temperature (Tg) may bebelow about 4° C., and more particularly below about −10° C. In versionswhere the adhesive material comprises caprolactone (PCL), the glasstransition temperature (Tg) may be below about −60° C. In versions wherethe adhesive material comprises polyethylene glycol (PEG), the glasstransition temperature (Tg) may be below about −35° C. Yet anotherexample of a suitable adhesive copolymer having a low glass transitiontemperature (Tg) is a 50/50 composition of caprolactone and glycolide(PCL/PGA), with a low inherent viscosity (IV) and low crystallinity.

F. Biologically Derived Extracellular Matrix with Infused ViscousAbsorbable Copolymer

In some instances, it may be desirable to provide a biologically derivedextracellular matrix (ECM) as buttress body (102) with an infusedviscous absorbable copolymer as an adhesive layer (104, 106) on upper orlower surfaces of buttress body (102). The below examples includevarious exemplary configurations through which a buttress assembly (100)may be formed by a combination of a biologically derived extracellularmatrix (ECM) with one or more infused viscous absorbable copolymeradhesive materials. In the present example, it is contemplated that theadhesive material comprises a natural based polymer such as thosereferred to herein. However, it should also be understood that syntheticbased polymers may be incorporated with the below teachings.

FIGS. 26-28 show an exemplary buttress assembly (900) that comprises abuttress body (902) and a plurality of discretely formed adhesiveregions (920, 922, 924, 926). Buttress body (902) may be configured andoperable just like buttress body (102) described above. Buttress body(902) of this particular example comprises a biologically derivedextracellular matrix (ECM) such as collagen. Adhesive regions (920, 922,924, 926) may comprise any of the various adhesive materials referred toherein. A first pair of proximal adhesive regions (920) are positionedat respective proximal corners of buttress body (902). A second pair oflateral adhesive region (922) are located near the longitudinal andlateral center of buttress body (902). A third pair of adhesive regions(924) are positioned at respective proximal corners of buttress body(902). A fourth pair of adhesive regions (926) extend longitudinallyalong the lateral mid-region of buttress body (902), such that adhesiveregions (926) are positioned to run alongside channel (62) of anvil (60)or channel (72) of staple cartridge (70). While adhesive regions (920,922, 924, 926) are provided in a particular pattern in this example, itshould be understood that buttress assembly (900) may instead haveadhesive regions in any other suitable pattern. It should also beunderstood that buttress assembly (900) may have a single layer ofadhesive material spanning along the full surface of buttress body(902), without having discretely formed adhesive regions. Other suitableconfigurations will be apparent to those of ordinary skill in the art inview of the teachings herein.

FIG. 27 shows how buttress body (902) provides a lattice defining aplurality of cells (908). Due to the presence of cells (908) and theporous nature of buttress body (902), some of the adhesive materialforming adhesive regions (920, 922, 924, 926) has entered some of thosecells (908), thereby partially infusing buttress body (902) with theadhesive material. In other words, buttress body (902) acts like asponge absorbing the adhesive material, allowing the adhesive materialto deform, surround, and essentially grab hold of the latticeconnections within buttress body (902).

In some instances, the adhesive material is initially applied tobuttress body (902) when the adhesive material is in a relatively highviscous form. Buttress assembly (900) is then heated to increase theviscosity of the adhesive material, causing the adhesive material toenter some of the cells (908) of buttress body (902). Buttress assembly(900) is then cooled or allowed to cool, causing the viscosity of theadhesive material to increase back to its previous state. Buttressassembly (900) may then be heated again as buttress assembly (900) isbeing applied to end effector (40) as described in greater detail below.In some other versions, the adhesive material already has a low enoughviscosity to enter cells (908) when the adhesive material is applied,without requiring the adhesive material to be heated. In other words,the adhesive material may wick into cells (908) of buttress body (902).In some such versions, a protective film (e.g., polytetrafluoroethylene(PTFE)) may be applied over the adhesive material to protect and/orcontain the adhesive material before buttress assembly (900) is appliedto end effector (900). Other suitable ways in which buttress assembly(900) may be formed and provided will be apparent to those of ordinaryskill in the art in view of the teachings herein.

FIG. 28 shows buttress assembly (900) being compressed between retainer(300) and anvil (60). As shown, this compression crushes the latticestructure of buttress body (902), collapsing cells (908) and therebydriving adhesive material out of buttress body (902) and into stapleforming pockets (64) (and/or into other surface features of underside(65)). This compression may be provided by closing anvil (60) againstbuttress assembly (900) and retainer (300) as described above. Whenanvil (60) is returned to the open position, the adhesive material instaple forming pockets (64) (and/or in other surface features ofunderside (65)) adheres buttress assembly (900) to underside (65), suchthat end effector (40) is loaded with buttress assembly (900) and isready for use. In some instances, retainer (300) and/or buttressassembly (900) may be heated just before buttress assembly (900) iscompressed between retainer (300) and anvil (60). Such heating mayincrease the viscosity of the adhesive material, thereby promotingmigration of the adhesive material into features of underside (65) andfurther thereby reducing the compression force required to urge theadhesive material into the features of underside (65).

FIG. 29 shows an exemplary alternative retainer (1000) that may be usedwith a buttress assembly such as buttress assembly (900). Retainer(1000) of this example comprises an upper side (1002), an underside(1004), a distally projecting tongue (1006), and a set of resilientlatches (1008). It should be understood that underside (1004), tongue(1006), and latches (1008) may be configured and operable just likeunderside (304), tongue (306), and latches (308) described above. Upperside (1002) of this example differs from upper side (302) in that upperside (1002) includes an array of upwardly protruding projections (1010)and a pair of longitudinally extending side rails (1012). Projections(1010) are configured to provide focused pressure to regions of buttressassembly (900) at regions corresponding to staple forming pockets (64)(and/or into other surface features of underside (65)), thereby furtherpromoting exit of the adhesive material from buttress body (902) intostaple forming pockets (64) (and/or into other surface features ofunderside (65)). Side rails (1012) are configured to contain adhesivematerial expelled from buttress body (902), preventing the adhesivematerial from spilling over the sides of retainer (1000). Other suitablestructural variations of retainer (1000) will be apparent to those ofordinary skill in the art in view of the teachings herein.

FIG. 30 shows another exemplary buttress assembly (1100) and retainer(1200). Buttress assembly (1100) of this example comprises a pair ofbuttress body sections (1102 a, 1102 b) that are joined by one or moretethers (1110) that span across a gap (1112) defined between buttressbody sections (1102 a, 1102 b). Gap (1112) extends longitudinally and issized to complement channels (62, 72) of anvil (60) and staple cartridge(70). Each buttress body section (1102 a, 1102 b) comprises abiologically derived extracellular matrix (ECM) such as collagen, suchthat each buttress body section (1102 a, 1102 b) has a lattice structuredefining a plurality of cells (not shown). Buttress assembly (1100)further comprises adhesive layer sections (1120 a, 1120 b) extendingalong respective body sections (1102 a, 1102 b). The adhesive materialforming adhesive layer sections (1120 a, 1120 b) may be formulated justlike the adhesive material forming adhesive regions (920, 922, 924, 926)described above. Adhesive layer sections (1102 a, 1102 b) each include aplurality of upwardly extending projections (1122). These projectionsare configured and positioned to correspond with staple forming pockets(64) on underside (65) of anvil (60).

Retainer (1200) of the present example has an upper surface (1202) thatincludes an upwardly projecting rib (1220) and a plurality of upwardlyextending projections (1222). Rib (1220) extends longitudinally and issized to complement channel (62) of anvil (60). As anvil (60) is drivento a closed position to compress buttress assembly (1100) against uppersurface (1202), rib (1220) may enter channel (62) and break tethers(1100). Rib (1220) may also ensure proper lateral alignment of retainer(1200) and buttress assembly (1100) with anvil (60). Various suitableforms that rib (1220) may take will be apparent to those of ordinaryskill in the art in view of the teachings herein. In some versions, rib(1220) is omitted. Projections (1222) are configured and positioned tocorrespond with projections (1122), staple forming pockets (64)underside (65) of anvil (60). Projections (1122, 1222) are configured tocooperate to provide focused pressure to regions of buttress assembly(1100) at regions corresponding to staple forming pockets (64) ofunderside (65) when anvil (60) is driven to a closed position againstbuttress assembly (1100) and retainer (1200), thereby further promotingexit of the adhesive material from buttress bodies (1102 a, 1102 b) intostaple forming pockets (64) of underside (65). Other suitable structuralvariations of buttress assembly (1100) and retainer (1200) will beapparent to those of ordinary skill in the art in view of the teachingsherein.

G. Naturally Derived Bioabsorbable Polymer Gel Adhesive

In some instances, it may be desirable to combine a naturally derivedbioabsorbable polymer gel with buttress body (102), in addition to or asan alternative to having one or more adhesive layers (104, 106) on upperor lower surfaces of buttress body (102), to removably secure buttressassembly (100) to deck (73) of staple cartridge (70) or underside (65)of anvil (60). The below examples include various exemplaryconfigurations through which one or more naturally derived bioabsorbablepolymer gel adhesive materials may be combined with a buttress body(102) to removably secure buttress assembly (100) to deck (73) of staplecartridge (70) or underside (65) of anvil (60). In the present example,it is contemplated that the adhesive material comprises a natural basedpolymer such as those referred to herein. However, it should also beunderstood that synthetic based polymers may be incorporated with thebelow teachings.

For instance, a naturally derived polymer may be provided in anabsorbable polymer solution to create a gel for attachment of buttressassembly (100) to deck (73) of staple cartridge (70) or underside (65)of anvil (60). A bioactive component that is a solid in dry form or agel in solution form is combined with an absorbable copolymer that doesnot include suspension of the degradation process until further exposureto water. For instance, dry polymer (powdered) of a water solublepolymer (e.g., carboxymethylcellulose (CMC)) may be mixed with a watersoluble liquid such as glycerin. When mixed, it forms a tacky andviscous compound. This compound remains very tacky and will stick to drysurfaces or substances, but it will not stick to wet or hydratedsubstances. When this compound comes into contact with water or a wetsurface it changes from sticky and tacky to very slippery andlubricious. This compound will also go into complete solution when addedto water more rapidly than the dry polymer powder alone. Suitablepolymers that may be used in such a composition include (but are notlimited to) hyaluronic acid, carboxymethylcellulose (CMC), polyvinylalcohol, poly vinyl acetate, higher molecular weight polyethylene glycol(PEG) (in solid form), or higher molecular weight polypropylene glycol(in solid form). Suitable liquids that may be used in such a compositioninclude (but are not limited to) glycerin, low molecular weightpolyethylene glycol (PEG) (in liquid form), or low molecular weightpolypropylene glycol (in liquid form).

In some versions, the adhesive material comprises a viscous cellulosebioabsorbable gel with particulate absorbable materials to increaseviscosity for attachment of buttress assembly (100) to deck (73) ofstaple cartridge (70) or underside (65) of anvil (60). In particular,the adhesive material may comprise a bioabsorbable liquid that hasparticulates mixed into the fluid to induce a gel-like suspension withhighly viscous features for application to buttress body (102) forattachment to deck (73) of staple cartridge (70) or underside (65) ofanvil (60).

1. Exemplary Retainer with Lower Adhesive Injection Region

FIGS. 31-32 show an exemplary retainer (1300) that may be used todispense a polymer adhesive gel (1330) directly at the site of endeffector (40) as a buttress body (1500) is being applied to end effector(40). The polymer adhesive gel (1330) is stored and contained in abarrel (1402) of syringe (1400) before dispensation. The gel iscommunicated by advancing a plunger (1406) of syringe (1400) relative tobarrel (1402), which drives the gel through needle (1404). Retainer(1300) of this example comprises an upper side (1302), an underside(1304), a distally projecting tongue (1306), a set of resilient latches(1308), and a set of injection ports (1310). It should be understoodthat upper side (1302), tongue (1306), and latches (1308) may beconfigured and operable just like upper side (302), tongue (306), andlatches (308) described above. Thus, retainer (1300) may be removablysecured to lower jaw (50) to apply buttress body (1500) to deck (73) ofstaple cartridge. Buttress body (1500) of this example may be configuredlike any other buttress body described herein.

As best seen in FIG. 32 , underside (1304) of retainer (1300) includes aplurality of downwardly extending projections (1312, 1314) and outerrails (1316). Projection (1312) is positioned and configured to extendinto channel (72) of staple cartridge (70). Projections (1314) arepositioned and configured to extend into staple pockets (74) of staplecartridge (70). Outer rails (1316) engage the perimeter of deck (73) ofstaple cartridge (70). Projections (1312, 1314) and rails (1316) serveas standoff features to provide a gap (1320) between the underside(1504) of buttress body (1500) and deck (73) of cartridge (70). Ports(1310) are in fluid communication with gap (1320). Thus, with needle(1404) inserted into port (1310), adhesive gel (1330) may be injectedinto gap (1320) by advancing plunger (1406) relative to barrel (1402).Projections (1312, 1314) may prevent adhesive gel (1330) from enteringchannel (72) and staple pockets (74), respectively as adhesive gel(1330) is injected into gap (1320). Similarly, outer rails (1316) mayprevent adhesive gel (1330) from escaping at the perimeter of deck (73)as adhesive gel (1330) is injected into gap (1320). In some versions,each port (1310) includes a self-sealing septum (not shown) thatprevents adhesive gel (1330) from escaping through port (1310) duringand after injection of adhesive gel (1330).

In some versions, underside (1304) of retainer (1300) is divided intofour quadrants. In some such versions, these quadrants are fluidlyisolated from each other, resulting in four separate gaps (1320). Insuch versions, needle (1404) may be inserted into each port (1310) toseparately fill each gap (1320) with adhesive gel (1330). In some otherversions, at least two of the quadrants are in fluid communication witheach other (e.g., the two quadrants on each side of projection (1312)),such that the operator may use either two or more than two ports (1310)to fill gap (1320) with adhesive gel (1330). Of course, any othersuitable number of ports (1310) and separate sections of gap (1320) maybe provided. Once a sufficient amount of adhesive gel (1330) has beeninjected, retainer (1300) may be held in place for any desired about oftime to allow adhesive gel (1330) to cure, set up, or otherwise changestate to a point where adhesive gel (1330) will sufficiently securebuttress body (1500) to deck (73) after retainer (1300) is removed.Alternatively, adhesive gel (1330) may already be in a state whereadhesive gel (1330) will sufficiently secure buttress body (1500) todeck (73) after retainer (1300) is removed, without requiring retainer(1300) to be kept in place for a significant period of time. In eithercase, once retainer (1300) is removed from end effector (40), thebuttress assembly formed by adhesive gel (1330) and buttress body (1500)will be secured to deck (73), such that loaded end effector (40) will beready for use.

2. Exemplary Retainer with Upper Adhesive Injection Region

FIG. 33 shows another exemplary alternative retainer (1600) that may beused to dispense a polymer adhesive gel directly at the site of endeffector (40) as a buttress body (not shown) is being applied to endeffector (40). Retainer (1600) of this example comprises a distallyprojecting tongue (1606), a set of resilient latches (1608), and aninjection port (1610). It should be understood that tongue (1606) andlatches (1608) may be configured and operable just like tongue (306) andlatches (308) described above. Thus, retainer (1600) may be removablysecured to lower jaw (50) to apply a buttress body to underside (65) ofanvil (60). The buttress body of this example may be configured like anyother buttress body described herein.

The upper side (not shown) of retainer (1600) may include a plurality ofupwardly extending projections. These upwardly extending projections maybe similar to projections (1312, 1314) of retainer (1300). Inparticular, the upwardly extending projections of retainer (1600) may beconfigured to extend into channel (62) and staple forming pockets (64)of anvil (60); and may be configured to serve as standoff features toprovide a gap (not shown) between the upper side of a buttress body(which would be overlaid on the upper side of retainer (1600)) andunderside (65) of anvil (60). Port (1610) would be in fluidcommunication with this gap, such that an adhesive gel may be injectedinto this port through a needle (1404) inserted into port (1610).Retainer (1600) also includes a lip portion (1616) that encompasses theouter perimeter of anvil (60). This lip portion (1616) may prevent theinjected adhesive gel from escaping the perimeter of anvil (60).Similarly, the upwardly extending projections of retainer (1600) mayprevent the adhesive gel from entering channel (62) and staple formingpockets (64) of anvil (60). In some versions, retainer (1600) onlyincludes an upwardly extending projection associated with channel (62),such that the injected adhesive gel is free to enter staple formingpockets (64). In some other versions, retainer (1600) lacks an upwardlyextending projection associated with channel (62). Other suitablevariations will be apparent to those of ordinary skill in the art inview of the teachings herein.

While retainer (1300) may be used to dispense an adhesive gel (1330)while anvil (60) is in an open position, it should be understood thatretainer (1600) is shown as being used to dispense an adhesive gel whileanvil (60) is in the closed position. In some other instances, retainer(1600) may be used to dispense an adhesive gel to secure a buttress bodyto underside (65) of anvil (60) while anvil (60) is in the openposition. It should also be understood that, in instances where a firstbuttress body is to be secured to deck (73) of staple cartridge (70) anda second buttress body (65) is to be secured to underside (65) of anvil(60), some versions of retainer (1600) may provide injection of adhesivegel via one or more ports into two different gaps. In particular, aretainer may be configured to provide injection of adhesive gel into afirst gap defined between a buttress body and underside (65) of anvil(60); and into a second gap defined between a buttress body and deck(73) of staple cartridge (70). Some such retainers may provide fillingof both gaps via a single port that is in fluid communication with bothgaps. Alternatively, each gap may have its own associated injectionport. Other suitable variations will be apparent to those of ordinaryskill in the art in view of the teachings herein.

3. Exemplary Adhesive Injector with Mixing Feature

FIGS. 34-35 show another exemplary retainer (1700) and injector assembly(1800) that may be used to apply a polymer adhesive gel (1840) to securebuttress bodies (1900) to underside (65) of anvil (60). Retainer (1700)comprises a distally projecting tongue (1706), a set of resilientlatches (1508), and a longitudinally extending, upwardly protrudingridge (1710). It should be understood that tongue (1706) and latches(1708) may be configured and operable just like tongue (306) and latches(308) described above. Thus, retainer (1700) may be removably secured tolower jaw (50). Ridge (1710) is configured and positioned to fit in aportion of channel (62), thereby preventing injected adhesive gel (1840)from entering channel (62). Each buttress body (1900) is positioned oneither side of ridge (1710). Each buttress body (1900) may be configuredlike any other buttress body described herein.

Injector assembly (1800) of this example comprises a dual syringeassembly (1810), a mixing assembly (1820), and a dispenser assembly(1830). Dual syringe assembly (1810) includes a pair of syringe barrels(1812) and a plunger (1814) that is operable to drive fluid from bothbarrels (1820) simultaneously. Each syringe barrel (1812) may include acomponent or set of components of adhesive gel (1840). For instance, insome versions one syringe barrel (1812) contains fibrin and the othersyringe barrel (1812) contains thrombin. In addition or in thealternative, one syringe barrel (1812) may contain a cellulose (e.g.,oxidized regenerated cellulose (ORC)), starch, chitin, glycogen in aglycerin, or a polyethylene glycol (PEG); while the other syringe barrel(1812) contains a water solution. Other suitable materials andcombinations will be apparent to those of ordinary skill in the art inview of the teachings herein.

Mixing assembly (1820) is in fluid communication with both syringebarrels (1812), such that fluid/gel injected from both barrels (1812)will enter mixing assembly (1820) simultaneously. As best seen in FIG.35 , mixing assembly (1820) includes a set of baffles (1822) that areconfigured to mix the two components from syringe barrels (1812) as thecomponents flow through mixing assembly (1820). Various suitableconfigurations and arrangements that may be used for baffles (1822) willbe apparent to those of ordinary skill in the art in view of theteachings herein.

In some versions, barrels (1812) and mixing assembly (1820) provide amixture of the contents of barrels (1812) at a 1:1 ratio. Alternatively,any other suitable mixture ratio may be provided. By way of exampleonly, some versions may provide a ratio of 7:1 fibrin to thrombin.

Dispenser assembly (1830) is in fluid communication with mixing assembly(1820), such that the liquid/gel (1840) that is mixed through mixingassembly (1820) will ultimately reach dispenser assembly (1830). As bestseen in FIG. 34 , dispenser assembly (1830) includes a set of distallyprojecting arms (1832). Each arm (1832) is configured to fit over acorresponding buttress body (1900). As best seen in FIG. 35 , theunderside of each arm (1832) includes a plurality of openings (1834).Openings (1834) are configured to convey the adhesive gel (1840) fromarm (1830) to the upper side of the corresponding buttress body (1900).In some versions, each arm (1832) further includes a downwardlyprojecting lip about the outer perimeter of arm (1832). Such a lip mayprevent the adhesive gel (1840) from escaping at the perimeter of arm(1832) during dispensation of the adhesive gel (1840). In addition or inthe alternative, retainer (1700) may include an upwardly extending lipthat is configured to prevent the adhesive gel (1840) from escaping atthe perimeter of arm (1832) during dispensation of the adhesive gel(1840). Other suitable variations will be apparent to those of ordinaryskill in the art in view of the teachings herein.

Once injector assembly (1800) has dispensed a sufficient amount ofadhesive gel (1840) onto buttress bodies (1900), injector assembly(1800) may be removed. Anvil (60) may then be driven to the closedposition to compress underside (65) against the dispensed adhesive gel(1840) and buttress bodies (1900). The adhesive gel (1840) may adherebuttress bodies (1900) to underside (65). Accordingly, as anvil (60) isreturned to the open position, adhesive gel (1840) and buttress bodies(1900) may remain secured to underside (65). Retainer (1700) may then beremoved from end effector (40) and end effector (40) will then be readyfor use.

H. Flowable Bioabsorbable Polymer Adhesive

In some instances, it may be desirable to combine a flowable (i.e., lowviscosity) adhesive material with buttress body (102), in addition to oras an alternative to having one or more adhesive layers (104, 106) onupper or lower surfaces of buttress body (102), to removably securebuttress assembly (100) to deck (73) of staple cartridge (70) orunderside (65) of anvil (60). One merely illustrative example of acomposition that may be used to provide a flowable adhesive material isa 50/50 copolymer of caprolactone and glycolide (PCL/PGA).

As another merely illustrative example, a flowable adhesive may beformulated in accordance with at least some of the teachings of U.S.Pub. No. 2005/0070929, entitled “Apparatus and Method for Attaching aSurgical Buttress to a Stapling Apparatus,” published Mar. 31, 2005, nowabandoned, the disclosure of which is incorporated by reference herein.For instance, a suitable flowable adhesive material may include one ormore elastomeric polymers or copolymers that have an inherent viscosity(IV) of from about 1.2 dL/g to about 4 dL/g, or more particularly aninherent viscosity (IV) of from about 1.2 dL/g to about 2 dL/g, or moreparticularly an inherent viscosity (IV) of from about 1.4 dL/g to about2 dL/g as determined at 25° C. in a 0.1 gram per deciliter (g/L)solution of polymer in hexafluoroisopropanol (HFIP). The elastomericpolymer may exhibit a high percent elongation and a low modulus, whilepossessing good tensile strength and good recovery characteristics. Theelastomeric polymer may exhibit a percent elongation greater than about200, preferably greater than about 500. It may also exhibit a modulus(Young's Modulus) of less than about 4000 psi, or more particularly lessthan about 20,000 psi. The properties, which measure the degree ofelasticity of the biodegradable elastomeric polymer, may be achievedwhile maintaining a tensile strength greater than about 500 psi, moreparticularly greater than about 1,000 psi; and a tear strength ofgreater than about 50 lbs/inch, more particularly greater than about 80lbs/inch.

Foam materials comprising elastomeric polymers (as a flowable adhesivematerial) may be formed by lyophilization, supercritical solvent foaming(e.g., as described in International Patent Pub. No. WO 91/09079,entitled “Use of Supercritical Fluids to Obtain Porous Sponges ofBiodegradable Polymers” published Jun. 27, 1991, the disclosure of whichis incorporated by reference herein), gas injection extrusion, gasinjection molding, or casting with an extractable material (e.g., salts,sugar or any other means known to those skilled in the art). In someinstances, biodegradable, biocompatible elastomeric foams are preparedby lyophilization. One suitable method for lyophilizing elastomericpolymers to form an exemplary buttress assembly (100) is described inU.S. Pat. No. 6,355,699, entitled “Process for Manufacturing BiomedicalFoams,” issued Mar. 12, 2002, the disclosure of which is incorporated byreference herein. As noted above, pharmaceutically active compounds maybe incorporated into the buttress assembly (100) to further treat thepatient, including but not limited to antibiotics, antifungal agents,hemostatic agents, anti-inflammatory agents, growth factors and thelike.

As another merely illustrative example, an aliphatic polyester may begenerally prepared by a ring-opening polymerization of the desiredproportions of one or more lactone monomers in the presence of anorganometallic catalyst and an initiator at elevated temperatures. Theorganometallic catalyst preferably is a tin-based catalyst, e.g.stannous octoate, and is present in the monomer mixture at a molar ratioof monomer to catalyst ranging from about 15,000/1 to about 80,000/1.The initiator typically is an alkanol (such as 1-dodecanol), a polyol(such as 1,2-propanediol, 1,3-propanediol, diethylene glycol, orglycerol, poly(ethylene glycol)s, polypropylene glycol)s andpoly(ethylene-co-propylene glycol)s), a hydroxyacid, or an amine, and ispresent in the monomer mixture at a molar ratio of monomer to initiatorranging from about 100/1 to about 5000/1. The polymerization typicallyis carried out at a temperature range from about 80° C. to about 220°C., more particularly from about 160° C. to 190° C., until the desiredmolecular weight and viscosity (IV) are achieved. The resulting materialmay be used to provide a flowable adhesive material for buttressassembly (100).

As yet another merely illustrative example, the flowable adhesivematerial may comprise cellulosic and aliphatic ester homopolymers andcopolymers made from polymers of the formula: [—O—R¹¹—C(O)—]_(y), whereR¹¹ is selected from the group consisting of —CR¹²H—, —(CH₂)₃—O—,—CH₂—CH₂—O—CH₂—, CR 12H—CH₂, —(CH₂)₄—, —(CH₂)_(z)—O— and—(CH₂)_(z)—C(O)—CH₂—; R¹² is hydrogen or methyl; z is an integer in therange of from 1 to 7; and y is an integer in the range of from about 10to about 20,000; blends of a viscous polyethylene glycol (PEG) liquidand a low melting solid polyethylene glycol (PEG) (solid at roomtemperature that melts at less than about 60° C.); biocompatiblemonosaccharides, disaccharides and polysaccharides (such as pectin) thatmay be mixed with a plasticizer (such as glycerine) to form a tackyadhesive and biocompatible proteins (such as gelatin) that may mixedwith a plasticizer (such as glycerine) to form a tacky adhesive.

Many nontoxic bioabsorbable aliphatic ester polymers that aresemi-crystalline solids or tacky liquids at room temperature may be usedas a releasable adhesive. The releasable adhesive may be flowable atbody temperature (37° C.) and in some instances will flow at roomtemperatures (25° C.). These liquids will may further have a low yieldpoint to avoid migration of the polymer. Examples of suitable tackyliquid copolymers are taught in U.S. Pat. No. 5,824,333, entitled“Injectable Liquid Copolymers for Soft Tissue Repair and Augmentation,”issued Oct. 20, 1998, the disclosure of which is incorporated byreference herein. Additionally, tacky microdispersions may also be usedsuch as those described in U.S. Pat. No. 5,599,852, entitled “PlylactoneHomo- and Copolymers,” issued Feb. 4, 1997, the disclosure of which isincorporated by reference herein.

A suitable flowable adhesive material may comprise a liquid copolymercomposed of in the range of from about 65 mole percent to about 35 molepercent of epsilon-caprolactone, trimethylene carbonate, ether lactone(which for the purpose of this invention is defined to be1,4-dioxepan-2-one and 1,5-dioxepan-2-one) repeating units orcombinations thereof with the remainder of the polymer being a pluralityof second lactone repeating units are preferred. The second lactonerepeating units may be selected from the group consisting of glycolicacid repeating units, lactic acid repeating units, 1,4-dioxanonerepeating units, 6,6-dialkyl-1,4-dioxepan-2-one, combinations thereofand blends thereof. Additionally, epsilon-caprolactone, trimethylenecarbonate, or an ether lactone may be copolymerized to provide a liquidcopolymer. Exemplary polymers that may be used as particulate solids arebioabsorbable polymers including homopolymers ofpoly(epsilon-caprolactone), poly(p-dioxanone), or poly(trimethylenecarbonate), copolymers of epsilon-caprolactone and trimethylenecarbonate, copolymers of epsilon-caprolactone and a plurality of secondlactone repeating units. The second lactone repeating units may beselected from the group consisting of glycolic acid repeating units,lactic acid repeating units, 1,4-dioxanone repeating units,1,4-dioxepan-2-one repeating units, 1,5-dioxepan-2-one repeating unitsand combinations thereof. The copolymers of epsilon-caprolactone may becomposed of from 99 mole percent to 70 mole percent epsilon-caprolactonewith the remainder of the polymer being a plurality of second lactonerepeating units.

The polymers may be linear, branched, or star branched; block copolymersor terpolymers; segmented block copolymers or terpolymers. Thesepolymers will also be purified to substantially remove unreactedmonomers that may cause an inflammatory reaction in tissue.

Further examples of liquid copolymers that may be used as a flowable,releasable adhesive are composed of in the range of from about 65 molepercent to about 35 mole percent epsilon-caprolactone or an etherlactone repeating unit with the remainder of the copolymer beingtrimethylene carbonate repeating units. Examples of suitable terpolymersare terpolymers selected from the group consisting ofpoly(glycolide-co-epsilon-caprolactone-co-p-dioxanone) andpoly(lactide-co-epsilon-caprolactone-co-p-dioxanone) wherein the molepercent of epsilon-caprolactone repeating units is from about 35 toabout 65 mole percent.

Further examples include terpolymers having in the range of from 40 to60 mole percent of epsilon-caprolactone repeating units. Examples ofliquid copolymer for use as the flowable, releasable adhesive may beselected from the group consisting ofpoly(epsilon-caprolactone-co-trimethylene carbonate),poly(lactide-co-trimethylene carbonate),poly(epsilon-caprolactone-co-p-d-ioxanone), poly(trimethylenecarbonate-co-p-dioxanone), poly(epsilon-caprolactone-co-lactide),poly(lactide-co-1,5-dioxepan-2-one-), andpoly(1,5-dioxepan-2-one-co-p-dioxanone),poly(lactide-co-1,4-dioxep-an-2-one), andpoly(1,4-dioxepan-2-one-co-p-dioxanone). The mole percent ofepsilon-caprolactone, trimethylene carbonate or ether lactone repeatingunits in these polymers should be in the range of from about 35 to about65 mole percent and more particularly in the range of from 40 to 60 molepercent. In some cases these liquid polymers will be statisticallyrandom copolymers. These polymers will also be purified to substantiallyremove unreacted monomers that may cause an inflammatory reaction intissue.

As noted above, exemplary polymers used as the flowable, releasableadhesive have an inherent viscosity (IV) as determined in a 0.1 g/dLsolution of hexafluoroisopropanol (HFIP) at 25° C. ranging from about0.1 dL/g to about 0.8 dL/g, more particularly from about 0.1 dL/g toabout 0.6 dL/g, and more particularly from 0.15 dL/g to 0.25 dL/g forliquid polymers. Additionally, blends of liquid and solid polyethyleneglycols (PEG) may be used as releasable adhesives. The liquidpolyethylene glycols (PEG) may have a molecular weight from about 200 toabout 600. The solid polyethylene glycols (PEG) may have a molecularweight from about 3400 to about 10,000. Generally it is theorized, butin no way limits the scope of this invention, that the low molecularweight liquid polyethylene glycols (PEG) plasticizes the solidpolyethylene glycols (PEG) to render the solid polyethylene glycols(PEG) tacky. Consequently, in some versions, the majority of thecomposition is be the solid polyethylene glycols (PEG) and moreparticularly between about 50 and about 80 percent by weight of thecomposition will be solid polyethylene glycols (PEG). For example, aliquid polyethylene glycol (PEG) with molecular weight of 400 (PEG 400)may be blended with a solid polyethylene glycol (PEG) with a molecularweight of about 2,000 (PEG 2000). The ratio of PEG 400 to PEG 2000 mayvary from about 40:60 to about 30:70. These blends may be formed bymixing the liquid polyethylene glycol (PEG) and the solid polyethyleneglycol (PEG) with constant stirring in a heated water bath until thesolid melts and a clear liquid solution is formed. After these solutionsare allowed to cool and the resulting mixture may be tested fortackiness and used if the desired tackiness is obtained.

Other suitable compositions that may provide a flowable adhesivematerial will be apparent to those of ordinary skill in the art in viewof the teachings herein. The below examples include various exemplaryconfigurations through which one or more flowable adhesive materials maybe combined with a buttress body (102) to removably secure buttressassembly (100) to deck (73) of staple cartridge (70) or underside (65)of anvil (60). In the present example, it is contemplated that theadhesive material comprises a synthetic based polymer such as thosereferred to herein. However, it should also be understood that naturallybased polymers may be incorporated with the below teachings.

In some instances, the adhesive material may be flowable at roomtemperature. Flowable adhesive materials may rely on their surfacetension, cohesion, viscosity (IV), and mechanical features of the twoattaching surfaces to create a bonding effect. The two attachingsurfaces could be completely smooth mating surfaces with the flowableadhesive material interposed between the two surfaces. Alternatively,the two attaching surfaces could have interlocking features where theflowable adhesive material takes a tortuous path when clamped betweenthe two surfaces, thereby maximizing the contact surfaces and surfacetension to hold them together. Flowable adhesive materials may alsointerface with small surface properties of a buttress body (102). Forinstance, in versions where buttress body (102) is formed as a fiberweave, the flowable adhesive material may flow into spaces between thefibers. Similarly, in versions where buttress body (102) is structuredlike a sponge, the flowable adhesive material may flow into variouscells of the structure. Other various ways in which a flowable adhesivematerial may interact with a buttress body (102) and either deck (73) ofstaple cartridge (70) or underside (65) of anvil (60) will be apparentto those of ordinary skill in the art in view of the teachings herein.

By way of example only, a flowable adhesive material may be injectedinto place between a buttress body (102) and either deck (73) of staplecartridge (70) or underside (65) of anvil (60) using any of thestructures and techniques described above with reference to FIGS. 31-35. In other words, a flowable adhesive material may be introduced andadministered just like an adhesive gel. Alternatively, any othersuitable structures or techniques may be used to provide a flowableadhesive material between a buttress body (102) and either deck (73) ofstaple cartridge (70) or underside (65) of anvil (60). Severaladditional examples will be described in greater detail below whileother examples will be apparent to those of ordinary skill in the art inview of the teachings herein.

1 Exemplary Buttress Assembly with Discrete Adhesive Droplets

FIGS. 36-37 show an exemplary buttress assembly (2000) that comprises abuttress body (2002), an impermeable layer (2004), and a layer offlowable adhesive material (2010). Buttress assembly (2000) ispositioned on an upper surface (2102) of a retainer (2100). Retainer(2100) may be configured and operable in accordance with any of thevarious retainers described herein. Buttress body (2002) may beconfigured in accordance with any buttress body described herein. Insome versions, buttress body (2002) comprises a porous media (e.g.,ETHISORB™ by Codman of Raynham, Mass.). Other suitable forms thatbuttress body (2002) may take will be apparent to those of ordinaryskill in the art in view of the teachings herein. As shown in FIG. 37 ,buttress body (2002) is provided in two sections (2002 a, 2002 b) thatare joined by one or more tethers (2030) that span across a gap (2032)defined between buttress body sections (2002 a, 2002 b). Gap (2032)extends longitudinally and is sized to complement channels (62, 72) ofanvil (60) and staple cartridge (70).

Impermeable layer (2004) is configured to prevent flowable adhesivematerial (2010) from flowing into buttress body (2002). Various suitablematerials that may be used to form impermeable layer (2004) will beapparent to those of ordinary skill in the art in view of the teachingsherein. In some variations, a semi impermeable layer may be used inplace of impermeable layer (2004). Such a semi impermeable layer mayallow a limited amount of the flowable adhesive material (2010) to flowinto buttress body (2002). By way of example only, such a semiimpermeable layer may comprise polydioxanone (PDS). It should beunderstood from the foregoing that buttress body (2002) and impermeablelayer (2004) (or a semi impermeable layer) may provide a laminate of afibrous and/or porous material and a homogenous film.

In the present example, flowable adhesive material (2010) is provided inthe form of several discrete droplets on top of impermeable layer(2004). An impermeable peel-away film (2020) is laid over flowableadhesive material (2010) and buttress body (2002). Film (2020) defines aplurality of pockets (2022) that are configured to contain flowableadhesive material (2010) in the form of discrete droplets. Film (2020)is configured to adhere to impermeable layer (2004) during storage andtransport of buttress assembly (2000), but may be peeled away to exposeflowable adhesive material (2010) right before buttress assembly (2000)is installed on end effector (40). The discrete droplets of adhesivematerial (2010) are sized and positioned to correspond with thepositioning of staple forming pockets (64) of anvil (60). Thus, thediscrete droplets of adhesive material (2010) are arranged in threelongitudinally extending linear arrays. Alternatively, any othersuitable arrangement may be used.

Retainer (2100) of the present example includes an upwardly projectingrib (2120). Rib (2120) extends longitudinally and is sized to complementchannel (62) of anvil (60). As anvil (60) is driven to a closed positionto compress buttress assembly (2000) against upper surface (2102), rib(2020) may enter channel (62) and break tethers (2020). Rib (2020) mayalso ensure proper lateral alignment of retainer (2000) and buttressassembly (2000) with anvil (60). Various suitable forms that rib (2120)may take will be apparent to those of ordinary skill in the art in viewof the teachings herein. In some versions, rib (2120) is omitted. Insome versions, upper surface (2102) further comprises a plurality ofupwardly extending projections that are positioned to correspond withthe positions of droplets of flowable adhesive material (2010) andstaple forming pockets (64). Such projections may thus be configured toprovide focused pressure to regions of buttress assembly (2000) atregions corresponding to staple forming pockets (64) of underside (65)when anvil (60) is driven to a closed position against buttress assembly(2000) and retainer (2100), thereby further promoting adhesion offlowable adhesive material (2010) in staple forming pockets (64) ofunderside (65).

2. Exemplary Cartridge with Adhesive Troughs

FIGS. 38-40 show an exemplary set of buttress bodies (2200), retainer(2300), and staple cartridge (2400). Buttress bodies (2200) are providedin two pairs in this example. As best seen in FIG. 39 , a lower pair ofbuttress bodies (2200) is configured such that each buttress body (2200)fits on a respective side of channel (2472) of staple cartridge (2400);while an upper pair of buttress bodies (2200) is configured such thateach buttress body (2200) fits on a respective side of channel (62) ofanvil (60). Each buttress body (2200) may be configured and operable inaccordance with any buttress body (2200) described herein.

Retainer (2300) of the present example has an upper surface (2310) and alower surface (2320). Upper surface (2310) includes a plurality ofupwardly extending projections (2312); an upwardly projecting,longitudinally extending rib (2314); and a pair of upwardly projecting,longitudinally extending side rails (2316). Projections (2312) areconfigured and positioned to correspond with staple forming pockets (64)on underside (65) of anvil (60). Rib (2314) is sized to complementchannel (62) of anvil (60). Lower surface (2320) includes a plurality ofdownwardly extending projections (2322); a downwardly projecting,longitudinally extending rib (2324); and a pair of downwardlyprojecting, longitudinally extending side rails (2326). Projections(2322) are configured and positioned to correspond with troughs (2404)that are formed in staple cartridge (2400) as will be described ingreater detail below. Rib (2324) is sized to complement channel (2472)of staple cartridge (2400).

Staple cartridge (2400) of the present example is substantiallyidentical to staple cartridge (70) described above. However, unlikestaple cartridge (70), staple cartridge (2400) of this example has adeck (2473) that includes upwardly extending ridges (2402) that surroundeach staple pocket (2474). These ridges (2402) thus define a trough(2404) on each side of channel (2472). A flowable adhesive material(2220) is provided in each trough (2404). As best seen in FIG. 40 ,ridges (2402) are configured to prevent flowable adhesive material(2220) from flowing into staple pockets (2474). When retainer (2300)loaded with buttress bodies (2200) is placed against staple cartridge(2400) as shown in FIG. 39 , buttress bodies (2200) are laid overflowable adhesive material (2220) and contact the top surfaces of eachridge (2402). Buttress bodies (2200) and ridges (2402) thus cooperate tocontain adhesive material (2220) in troughs (2404). It should beunderstood that there are numerous ways in which flowable adhesivematerial (2220) may be introduced into troughs (2404), before or afterbuttress bodies (2200) are placed against staple cartridge (2400). Byway of example only, flowable adhesive material (2220) may be injectedinto troughs (2404) as described above, before or after buttress bodies(2200) are placed against staple cartridge (2400). As another merelyillustrative example, staple cartridge (2400) may be pre-loaded withflowable adhesive material (2220) in troughs (2404), with an impermeablepeel away film being secured to ridges (2402). In such versions, thepeel away film may contain the flowable adhesive material (2220) introughs (2404) during storage and transport; and may then be peeled awayright before buttress bodies (2200) are placed against staple cartridge(2400). Other suitable ways in which flowable adhesive material (2220)may be provided and contained in troughs (2404) will be apparent tothose of ordinary skill in the art in view of the teachings herein.

Similarly, flowable adhesive material (2220) is positioned in stapleforming pockets (64) of anvil (60). Such flowable adhesive material(2220) may be provided and contained in staple forming pockets (64)using any of the techniques described above with respect to providingand containing flowable adhesive material (2220) in troughs (2404). Asanother merely illustrative example, buttress bodies (2200) may beconfigured with discrete droplets of adhesive material (2220), with apeel-away film layer used to contain the adhesive material (2220) in theform of discrete droplets, similar to buttress assembly (2000) describedabove. Other suitable ways in which flowable adhesive material (2220)may be provided and contained in staple forming pockets (64) will beapparent to those of ordinary skill in the art in view of the teachingsherein.

When retainer (2300) loaded with buttress bodies (2200) is positionedbetween anvil (60) and staple cartridge (2400), with flowable adhesivematerial (2220) in troughs (2404) and either in staple forming pockets(64) or in positions to enter staple forming pockets (64), anvil (60)may be brought to a closed position as shown in FIG. 39 . At this stage,projections (2312) are configured to provide focused pressure to regionsof buttress bodies (2200) at regions corresponding to staple formingpockets (64); while projections (2322) are configured to provide focusedpressure to regions of buttress bodies (2200) at regions correspondingto troughs (2404). In addition, ribs (2314, 2324) enter correspondingchannels (62, 2472) and prevent flowable adhesive material (2220) fromentering channels (62, 2472). Ribs (2314, 2324) may also ensure properlateral alignment of retainer (2300) and buttress bodies (2200) withanvil (60) and staple cartridge (2400). Side rails (2316, 2326) areconfigured to further contain flowable adhesive material (2220). Siderails (2316, 2326) may also assist in ensuring proper lateral alignmentof retainer (2300) and buttress bodies (2200) with anvil (60) and staplecartridge (2400). After anvil (60) has been brought to the closedposition, anvil (60) may be brought back to the open position andretainer (2300) may be removed, leaving buttress bodies (2200) adheredto underside (65) of anvil (60) and deck (2473) of staple cartridge(2470).

As another merely illustrative variation, buttress bodies (2200) mayeach define a plurality of pockets that are configured to containflowable adhesive material (2220) in the form of discrete droplets. Insome such versions, a flat impermeable peel-away film is laid overflowable adhesive material (2220) and each buttress body (2200),containing flowable adhesive material (2220) in the pockets of buttressbody (2200). In some other versions, such peel-away film also defines aplurality of pockets that are configured to cooperate with the pocketsof buttress body (2220) to contain flowable adhesive material (2220) inthe form of discrete droplets. It should be understood that suchvariations may be used in combination with staple cartridge (2400) orstaple cartridge (70).

As yet another merely illustrative variation, each buttress body (2200)may include a plurality of discrete regions of increased thickness. Inthe pair of upper buttress bodies (2200), these discrete regions ofincreased thickness may be located at positions corresponding to stapleforming pockets (64). In the pair of lower buttress bodies (2200), thesediscrete regions of increased thickness may be located at positionscorresponding to troughs (2404). The discrete regions of increasedthickness may serve functions similar to those of projections (2312,2322), such that projections (2312, 2322) may be omitted. In particular,discrete regions of increased thickness in buttress bodies (2200) mayprovide focused pressure to regions of buttress bodies (2200) at regionscorresponding to staple forming pockets (64) and troughs (2404). Eachbuttress body (2200) may also have regions of increased thickness atlocations corresponding to channels (62, 2472), such that regions ofincreased thickness in buttress bodies (2200) may serve as structuralsubstitutes for (and functional equivalents of) ribs (2314, 2324).

3. Exemplary Retainer with Foam Biasing Features

FIGS. 41-42 show another exemplary alternative retainer (2500) that isconfigured for use with a buttress assembly (2600). Retainer (2500) ofthis example comprises a distally projecting tongue (2506); a set ofresilient latches (2508); an upwardly projecting, longitudinallyextending rib (2510); a pair of upwardly projecting, longitudinallyextending side rails (2512); and a set of foam members (2520, 2522). Itshould be understood that tongue (2506) and latches (2508) may beconfigured and operable just like tongue (306) and latches (308)described above. Thus, retainer (2500) may be removably secured to lowerjaw (50) to apply a buttress body to underside (65) of anvil (60). Itshould also be understood that rib (2510) and rails (2512) may beconfigured and operable just like rib (2314) and side rails (2316)described above. Thus, rib (2510) and rails (2512) may assist inensuring proper positioning of retainer (2500) and may further assist incontaining flowable adhesive material at appropriate locations.

Buttress assembly (2600) is configured substantially similar to buttressassembly (2000) described above. In particular, buttress assembly (2600)comprises a pair of buttress bodies (2602), each having a layer offlowable adhesive material (2610, 2612) in discrete regions. Inparticular, each buttress body (2602) has a large distal region offlowable adhesive material (2610) and several smaller regions offlowable adhesive material (2612) proximal to the distal region offlowable adhesive material (2610). Buttress bodies (2602) may beconfigured in accordance with any buttress body described herein. Insome versions, an impermeable or semi-impermeable layer is positionedover each buttress body (2602), interposed between buttress body (2602)and flowable adhesive material (2610, 2612), to thereby prevent orrestrict the flow of flowable adhesive material (2610, 2612) intobuttress body (2602).

An impermeable peel-away film (2620) is laid over flowable adhesivematerial (2610, 2612) and buttress body (2602). Film (2620) defines aplurality of pockets (2622, 2624) that are configured to containflowable adhesive material (2610, 2612) in the form of discretedroplets. Film (2620) is configured to adhere to buttress body (2602)(or an impermeable layer or semi-impermeable layer that is laid overbuttress body (2602)) during storage and transport of buttress assembly(2600), but may be peeled away to expose flowable adhesive material(2610, 2612) right before buttress assembly (2600) is installed on endeffector (40). Pocket (2622) is larger than pockets (2624), such thatpockets (2622) are sized to correspond with the larger size of distalregion of flowable adhesive material (2610); while pockets are sized tocorrespond with the smaller size of smaller regions of flowable adhesivematerial (2612).

Foam members (2520, 2522) comprise a pair of distal foam members (2520)and a pair of proximal foam members (2522). Foam members (2520, 2522)may comprise any suitable foam material. Each foam member (2520, 2522)is configured to provide an upward bias to buttress assembly (2600),though foam members (2520, 2522) are compressible. It should beunderstood that foam members (2520, 2522) may provide a homogenouspressure urging buttress assembly (2600) into engagement with underside(65) of anvil (60) when anvil (60) compresses buttress assembly (2600)against retainer (2500). While foam members (2520, 2522) are formed asdiscrete blocks at distal and proximal regions of retainer (2500) inthis example, foam members (2520, 2522) may alternatively have any othersuitable configuration. By way of example only, foam members (2520,2522) may extend longitudinally along the full length of upper surface(2502) of retainer (2500). Other suitable configurations andcompositions that may be used for foam members (2520, 2522) will beapparent to those of ordinary skill in the art in view of the teachingsherein.

4. Exemplary Buttress Assembly with Adhesive Retaining Pockets

As another merely illustrative variation, a buttress body may define aplurality of pockets that are configured to contain a flowable adhesivematerial in the form of discrete droplets. FIGS. 43A-44 show anexemplary buttress assembly (2700) that provides such structure andfunctionality. In particular, FIG. 43A shows buttress assembly (2700) ina first state of manufacture, where an impermeable layer (2704) is laidover a buttress body (2702). Various suitable materials that may be usedto form impermeable layer (2704) and buttress body (2702) will beapparent to those of ordinary skill in the art in view of the teachingsherein. As shown in FIG. 43B, impermeable layer (2704) of this exampleis absorbed into the upper region of buttress body (2702) to provide asurface coating. By way of example only, impermeable layer (2704) may beprovided initially in a liquid form, such that buttress body (2702)soaks in the liquid; then the liquid soon cures to form an absorbedimpermeable layer and surface coating. Again, various suitable materialsand techniques that may be used to provide this structure andoperability will be apparent to those of ordinary skill in the art inview of the teachings herein. After impermeable layer (2704) has beensufficiently absorbed, a heated stamping member (2750) is driven intobuttress assembly (2700) as shown in FIG. 43C, forming a recess (2710)that stays formed after stamping member (2750) is removed. In thepresent example, one or more heated stamping members (2750) are used toform several recesses (2710) in buttress assembly (2700), as shown inFIG. 44 .

Recesses (2710) are sized and positioned to correspond with regions ofunderside (65) of anvil (60) that are located between staple formingpockets (64). In some versions, each recess (2710) is formed as alongitudinally extending trough or channel that extends along nearly thefull length of buttress assembly (2700). In some other versions,recesses (2700) are provided in linearly extending arrays, similar tothe arrangement of droplets of adhesive material (2010) described abovewith reference to FIGS. 36-37 . Other suitable configurations andarrangements will be apparent to those of ordinary skill in the art inview of the teachings herein. After recesses (2710) are formed, aflowable adhesive material (2720) is deposited into each recess (2710).By way of example only, flowable adhesive material (2720) may beinjected into recesses (2710) as described above. In some versions, aflat impermeable peel-away film is laid over flowable adhesive material(2720) and buttress body (2702), containing flowable adhesive material(2720) in the pockets recesses (2710)). In some other versions, suchpeel-away film also defines a plurality of pockets that are configuredto cooperate with recesses (2710) to contain flowable adhesive material(2720) in the form of discrete droplets that extend above the plane ofthe upper surface (2706) of buttress assembly (2700).

FIG. 44 shows adhesive assembly (2700) with adhesive material (2720)interposed between anvil (60) and retainer (2800). Retainer (2800) ofthis example has an upper surface (2802) comprising a plurality ofupwardly extending projections (2804) that are positioned to correspondwith the positions of recesses (2710) and the regions of underside (65)of anvil (60) that are located between staple forming pockets (64). Suchprojections (2804) may thus be configured to provide focused pressure toregions of buttress assembly (2700) the regions of underside (65) ofanvil (60) that are located between staple forming pockets (64) whenanvil (60) is driven to a closed position against buttress assembly(2700) and retainer (2800), thereby further promoting adhesion offlowable adhesive material (2720) to underside (65).

As described above, buttress assembly (2700) provides positioning offlowable adhesive material (2720) at the regions of underside (65) ofanvil (60) that are located between staple forming pockets (64). In someother variations, buttress assembly (2700) provides positioning offlowable adhesive material (2720) at the regions of underside (65) ofanvil (60) that correspond with staple forming pockets (64). It shouldbe understood that other examples described herein as positioning anadhesive at regions corresponding with staple forming pockets (64) maybe conversely varied. In other words, instead of positioning theadhesive at regions corresponding with staple forming pockets (64), suchversions may position the adhesive at the regions of underside (65) thatare located between staple forming pockets (64). Other suitablelocations on underside (65) where adhesive may be positioned will beapparent to those of ordinary skill in the art in view of the teachingsherein.

Those of ordinary skill in the art will recognize that some surgicalprocedures may require end effector (40) to be actuated several timesduring a single surgical procedure. In settings where staple cartridge(70) may only be used for a single actuation, this may require endeffector (40) to be withdrawn from the patient to replace a spent staplecartridge (70) with a new staple cartridge (70). At this stage, beforeend effector (40) is inserted back into the patient for the nextactuation, the operator may also reload end effector with one or morenew buttress assemblies. After this process is repeated a certain numberof times, some adhesive material may begin to build up on anvil (60). Itmay therefore be desirable to clean anvil (60) at some point during thesurgical procedure. To facilitate such cleaning, the adhesive materialmay be water soluble. In such instances, the operator may simply swishend effector (40) in water or hold end effector (40) under flowing waterto clean built-up adhesive material from anvil (60). In addition or inthe alternative, a brush and/or other kind of cleaning implement may beused to provide mechanical agitation to thereby clean built-up adhesivematerial from anvil (60). Other suitable ways in which anvil (60) may becleaned will be apparent to those of ordinary skill in the art in viewof the teachings herein.

I. Exemplary Surgical Staple Buttress with Integral Attachment andReinforcement Features

In some instances, it may be desirable to integrate attachment andreinforcement features into buttress body (102), in addition to or as analternative to having one or more adhesive layers (104, 106) on upper orlower surfaces of buttress body (102). Such integral attachment andreinforcement features may enhance the attachment and reinforcement ofbuttress body (102) relative to tissue (90), relative to deck (73) ofstaple cartridge (70) and/or relative to underside (65) of anvil (60).The below examples include various exemplary configurations throughwhich one or more attachment and reinforcement features may be combinedwith a buttress body (102) to enhance the attachment and reinforcementof buttress body (102) relative to tissue (90), relative to deck (73) ofstaple cartridge (70) and/or relative to underside (65) of anvil (60).In the present example, it is contemplated that the adhesive materialscomprise a synthetic based polymer such as those referred to herein. Byway of example only, an adhesive material composition that may be usedin the below example may include a 65/35 a copolymer of caprolactone andglycolide (PCL/PGA) having a low inherent viscosity (IV) and lowcrystallinity. Other suitable compositions will be apparent to those ofordinary skill in the art in view of the teachings herein. It shouldalso be understood that naturally based polymers may be incorporatedwith the below teachings.

1. Exemplary Buttress Assembly with Post-Stapling Adhesive Flow

FIGS. 45-46B show an exemplary buttress assembly (2900) that comprises abuttress body (2902) that contains an adhesive adjunct material (2904).Adhesive adjunct material (2904) may have a low viscosity enablingadhesive adjunct material (2904) to flow out of buttress body (2902)when buttress body (2902) is compressed. Various suitable compositionsthat may be used to provide adhesive adjunct material (2904) will beapparent to those of ordinary skill in the art in view of the teachingsherein. Buttress body (2902) may have a fibrous structure, porousstructure, and/or any other suitable kind of structure that isconfigured to absorb or otherwise contain adhesive adjunct material(2904). Various suitable materials and structures that may be used toprovide buttress body (2902) will be apparent to those of ordinary skillin the art in view of the teachings herein.

A pressure sensitive, impermeable adhesive film (2910) is secured to onesurface of buttress body (2902). Being impermeable, adhesive film (2910)is configured to prevent adhesive adjunct material (2904) from flowingout of that surface of buttress body (2902). Adhesive film (2910) isalso configured to removably secure buttress assembly (2900) tounderside (65) of anvil (60) or deck (73) of staple cartridge (70). Inparticular, adhesive film (2910) includes a pressure sensitive adhesivethat provides enough adhesive strength to temporarily secure buttressassembly (2900) to underside (65) of anvil (60) or deck (73) of staplecartridge (70); yet the pressure sensitive adhesive also permitsadhesive film (2910) to be pulled off of underside (65) of anvil (60) ordeck (73) of staple cartridge (70) after end effector (40) has beenactuated and staples (77) have been driven through buttress assembly(2900). Various suitable materials that may be used to form adhesivefilm (2910) will be apparent to those of ordinary skill in the art inview of the teachings herein. Similarly, various suitable materials thatmay be used to provide a pressure sensitive adhesive on or in adhesivefilm (2910) will be apparent to those of ordinary skill in the art inview of the teachings herein.

It should be understood that, when buttress assembly (2900) is loaded onretainer (300), the surface of upper side (302) or lower side (304)(depending on which side buttress assembly (2900) is loaded onto) mayprevent adhesive adjunct material (2904) from flowing out of the surfaceof buttress body (2902) that is opposite to adhesive film (2910). FIGS.45-46B show two buttress assemblies (2900), such that one buttressassembly (2900) would have been loaded onto upper side (302) of retainer(300) while the other buttress assembly (2900) would have been loadedonto lower side (304) of retainer (300). FIG. 45 in particular showsstapler drivers (75) driving staples (77) through tissue (90) andthrough both buttress assemblies (2900) as end effector (40) is beingactuated. As shown in FIG. 46A, when staple (77) is initially driventhrough tissue (90) and buttress assemblies (2900), legs (220) of staple(77) tear through film (2910), creating gaps (2920) around crown (210)and staple legs (220). These gaps (2920) provide a path for adhesiveadjunct material (2904) to flow out of buttress body (2902). Moreover,the series of applied staples (77) compress buttress assemblies (2900)against tissue (90), thereby urging adhesive adjunct material (2904) outof buttress body (2902) and into gaps (2920) as shown in FIG. 46B. Thisexpelled adhesive adjunct material (2904) flows onto crown (210) andregions of legs (220) that would otherwise be exposed. The expelledadhesive adjunct material (2904) may eventually cure and thereby furtherreinforce the structural integrity of the applied buttress assembly(2900); and/or further reinforce the attachment of staples (77) tobuttress assemblies (2900). The expelled adhesive adjunct material(2904) may also provide a hemostatic effect by blocking the flow ofblood that might otherwise occur through gaps (2920).

In some variations of buttress assembly (2900), the adhesive adjunctmaterial (2904) is provided in a layer that is laid over buttress body(2902) (in addition to or in lieu of being absorbed in or otherwisecontained in buttress body (2902)). For instance, the adhesive adjunctmaterial (2904) may be provided in a layer that is either used toreplace impermeable adhesive film (2910) or in a layer that isinterposed between buttress body (2902) and impermeable adhesive film(2910). Other suitable configurations will be apparent to those ofordinary skill in the art in view of the teachings herein.

2. Exemplary Buttress Assembly with Integral Fastening Strands

FIGS. 47-51 show another exemplary buttress assembly (3000) with anexemplary alternative retainer (3100). Two buttress assemblies (3000)are shown, including one buttress assembly (3000) that is positioned toattach to underside (65) of anvil (60) and another buttress assembly(300) that is positioned to attach to a deck (3273) of a staplecartridge (3270). As best seen in FIG. 48 , each buttress assembly(3000) of this example comprises a buttress body (3002) with a set offastening strands (3010) woven therethrough. Buttress body (3002) may beconfigured and operable in accordance with any of the various buttressbodies referred to herein. By way of example only, fastening strands(3010) may comprise VICRYL® (polyglactin 910) suture material by EthiconUS, LLC. Alternatively, any other suitable material(s) may be used. Inthe present example, strands (3010) are provided only in a series ofsmall, discrete woven regions (3012). In other words, strands (3010) arenot woven throughout the entire buttress body (3002) in this example.The discrete woven regions (3012) of strands (3010) are positioned atlocations where staples (77) will be driven through buttress assembly(3000), as will be described in greater detail below. In some otherversions, strands (3010) are woven throughout the entire buttress body(3002) or in some other arrangement.

As also shown in FIG. 48 , buttress assembly (3000) further includes aset of reinforcement members (3020, 3022). Reinforcement members (3020,3022) may also comprise VICRYL® (polyglactin 910) suture material and/orany other suitable material(s). Each reinforcement member (3020) extendslongitudinally along the full length of buttress body (3002).Reinforcement members (3022) extend transversely across the full widthof buttress body (3002). Reinforcement members (3022) also span a gap(3004) defined between a pair of buttress bodies (3002), providing aconnection of buttress bodies (3002) across gap (3004). In someversions, reinforcement members (3020, 3022) pass through discrete wovenregions (3012) of strands (3010), such that reinforcement members (3020,3022) are included in the weave at some of the discrete woven region(3012). In addition or in the alternative, reinforcement members (3020,3022) may themselves be at least partially woven through buttress bodies(3002).

As best seen in FIG. 49 , buttress assembly (3000) further includes animpermeable layer (3030) laid over buttress body (3002). In the presentexample, strands (3010) and reinforcement members (3022) are partiallywoven through impermeable layer (3030); while reinforcement membermembers (3022) are positioned over impermeable layer (3030). In someother versions, impermeable layer (3030) is substituted with a semiimpermeable layer, such as a layer of polydioxanone (PDS) and/or someother material(s). Various suitable materials that may be used to formimpermeable layer (3030) (or a semi impermeable substitute therefor)will be apparent to those of ordinary skill in the art in view of theteachings herein.

As best seen in FIG. 50 , buttress assembly (3000) further includes animpermeable peel-away film (3040) laid over impermeable layer (3030).Peel-away film (3040) defines a plurality of pockets (3042) that areconfigured to retain a flowable adhesive material (3050) (shown in FIG.51 ) in an array of discretely formed droplets on impermeable layer(3030). Peel-away film (3040) is configured to adhere to impermeablelayer (3030) during storage and transport of buttress assembly (3000),but may be peeled away to expose the flowable adhesive material (3050)under pockets (3042) right before buttress assembly (3000) is installedon end effector (40). The discrete droplets of adhesive material (3050)are sized and positioned to correspond with the positioning of stapleforming pockets (64) of anvil (60). Thus, the discrete droplets ofadhesive material (3050) and pockets (3042) are arranged in threelongitudinally extending linear arrays. Alternatively, any othersuitable arrangement may be used. Various suitable materials that may beused to form peel-away film (3040) will be apparent to those of ordinaryskill in the art in view of the teachings herein.

Referring back to FIG. 47 , retainer (3100) has an upper surface (3110)and a lower surface (3120). A first pair of buttress assemblies (3000)are positioned on upper surface (3110) for adhesion of those buttressassemblies (3000) to underside (65) of anvil (60). A second pair ofbuttress assemblies (3000) are positioned on lower surface (3120) foradhesion of those buttress assemblies (3000) to deck (3273) of staplecartridge (3270). Upper surface (3110) includes an upwardly projecting,longitudinally extending rib (3114). Rib (3114) is sized to complementchannel (62) of anvil (60). Lower surface (3120) also includes adownwardly projecting, longitudinally extending rib (3124), which issized to complement channel (3272) of staple cartridge (3270). Whenanvil (60) is moved to a closed position to compress retainer (3100) andbuttress assemblies (3000) between anvil (60) and staple cartridge(3270), ribs (3114, 3124) enter corresponding channels (62, 3472) andprevent flowable adhesive material (3050) from entering channels (62,3472). Ribs (3114, 3124) may also ensure proper lateral alignment ofretainer (3100) and buttress bodies (3000) with anvil (60) and staplecartridge (3270).

Upper surface (3110) of the present example further includes a pluralityof upwardly extending projections (3112). While projections (3112) areonly shown on one side of rib (3114), it should be understood thatprojections (3112) may also be located on the other side of rib (3114).Projections (3112) are configured and positioned to correspond withstaple forming pockets (64) on underside (65) of anvil (60); and pockets(3042) of peel-away film (3040). When anvil (60) is moved to a closedposition to compress retainer (3100) and buttress assemblies (3000)between anvil (60) and staple cartridge (3270), projections (3112) areconfigured to provide focused pressure to regions of buttress bodies(3002) at regions corresponding to staple forming pockets (64) thedroplets of adhesive material (3050) formed by pockets (3042). While notshown, it should be understood that lower surface (3120) may alsoinclude downwardly extending projections, similar to projections (3112),to provide focused pressure to selected regions of buttress bodies(3002).

As also shown in FIG. 47 , staple cartridge (3270) of the presentexample is substantially similar to staple cartridge (70) in that staplecartridge (3270) of this example includes channel (3272) and staplepockets (3274). However, staple cartridge (3270) of this example differsfrom staple cartridge (70) in that staple cartridge (3270) of thisexample includes upwardly extending walls (3280) that surround eachstaple pocket (3274), the outer edges of deck (3273), and the edges ofdeck (3273) adjacent to channel (3272). Walls (3280) thus define troughs(3290) that are configured to prevent adhesive material (3050) fromflowing into staple pockets (3274), over the outer edges of deck (3273),and into channel (3272). In some other variations, staple cartridge(3270) is simply substituted with staple cartridge (70) or some otherkind of staple cartridge.

FIG. 51 shows tissue (90) after an end effector formed by anvil (60) andstaple cartridge (3270) has been actuated through the tissue (90). Asshown, staples (77) secure buttress assemblies (3000) to the tissue(90). Crown (210) and legs (220) of each staple (77) capture strands(3010) and reinforcement members (3022), providing an attachment thatmay be more secure than what might otherwise be provided if buttressbody (3002) lacked strands (3010) and reinforcement members (3022). Itshould be understood that, when firing beam (82) is advanced distallyduring actuation of the end effector, knife member (80) severs theportions of reinforcement members (3022) that span across gap (3004).

As is also shown in FIG. 51 , some of the adhesive material (3050)remains on impermeable layer (3030). In some instances, this adhesivematerial (3050) may flow into gaps that might otherwise be presentadjacent to crowns (210) and/or legs (220). The adhesive material (3050)may thus further reinforce the structural integrity of the appliedbuttress assembly (3000); and/or further reinforce the attachment ofstaples (77) to buttress assemblies (3000). The adhesive material (3050)may also provide a hemostatic effect by blocking the flow of blood thatmight otherwise occur through gaps that might otherwise be presentadjacent to crowns (210) and/or legs (220). In some other variations,buttress assemblies (3000) are configured such that an appreciableamount of adhesive material (3000) is no longer present on impermeablelayer (3030) after staples (77) are fired. Other suitable arrangementsand compositions will be apparent to those of ordinary skill in the artin view of the teachings herein.

3. Exemplary Buttress Assembly with Heat Sensitive Strands

FIGS. 52-54 show another exemplary buttress assembly (3300). Buttressassembly (3300) of this example comprises a buttress body (3302) with apair of heat sensitive strands (3310) woven through buttress body(3302). Buttress body (3302) may be formed in accordance with anybuttress body referred to herein. Each heat sensitive strand (3310) iswoven through buttress body (3302) such that heat sensitive strand(3310) extends along the full length of buttress body (3302). Heatsensitive strands (3310) are parallel to each other and are spaced apartby a distance complementing the lateral width of channels (62, 72). Heatsensitive strands (3310) are formed of a material that will melt at arelatively low temperature and adhere to a surface that it is in contactwith when it melts and cools. The melting temperature (Tm) of heatsensitive strands (3310) is lower than the melting temperature (Tm) ofbuttress body (3302).

By way of example only, heat sensitive strands (3310) may comprisepolydioxanone (PDS). In some such versions, buttress body (3302)comprises VICRYL® (polyglactin 910) material by Ethicon US, LLC, heatsensitive strands (3310) comprise polydioxanone (PDS), and buttressassembly (3300) is formed as a woven fleece material made from a 7:1blend of VICRYL®:PDS that is heat treated to shrink polydioxanone (PDS)and bond individual fibers in the fleece together. Alternatively, anyother suitable blend ratio may be used. In some versions where buttressassembly (3300) comprises a woven fleece material made from a blend ofVICRYL® material and polydioxanone (PDS), the fleece may be attached toa polydioxanone (PDS) film that may be heated to secure buttressassembly (3300) to underside (65) of anvil (60) or deck (73) of staplecartridge (70).

As another merely illustrative example, buttress assembly (3300) may beconstructed in accordance with at least some of the teachings of U.S.Pat. No. 5,686,090, entitled “Multi-Layered Implant,” issued Nov. 11,1997, the disclosure of which is incorporated by reference herein.Various other suitable materials that may be used to form heat sensitivestrands (3310) will be apparent to those of ordinary skill in the art inview of the teachings herein. While buttress assembly (3300) onlyincludes two heat sensitive strands (3310) in the depicted example, itshould be understood that any other suitable number of heat sensitivestrands (3310) may be incorporated into buttress assembly (3300) ifdesired.

FIG. 53 shows buttress assembly (3300) applied to underside (65) ofanvil (60). As shown, heat sensitive strands (3310) are positioned onrespective regions of underside (65) that are adjacent to channel (62).When buttress assembly (3300) is so positioned, heat sensitive strands(3310) may be heated to their melting point; then allowed to cool tothereby adhere buttress assembly (3300) to underside (65). By way ofexample only, buttress assembly (3300) may be applied to underside (65)using a modified version of retainer (300). For instance, such amodified version of retainer (300) may include a heating element at orunder upper side (302). The heating element may be activated while anvil(60) is clamping down on buttress assembly (3300). Such a modifiedversion of retainer (300) may also include a coating such aspolytetrafluoroethylene (PTFE) to prevent heat sensitive strands (3310)from adhering to upper side (302). In addition or in the alternative,retainer (300) may include surface features that are configured toprevent heat sensitive strands (3310) from adhering to upper side (302).It should also be understood that heat sensitive strands (3310) may bewoven through buttress body (3302) in such a way that heat sensitivestrands (3310) will not contact upper side (302) of the modifiedretainer (300). Other suitable structures and techniques that may beused to provide heat to heat sensitive strands (3310) will be apparentto those of ordinary skill in the art in view of the teachings herein.

FIG. 54 shows buttress assembly (3300) applied to deck (73) of staplecartridge (70). As shown, heat sensitive strands (3310) are positionedon respective regions of deck (73) that are adjacent to channel (72).When buttress assembly (3300) is so positioned, heat sensitive strands(3310) may be heated to their melting point; then allowed to cool tothereby adhere buttress assembly (3300) to deck (73). By way of exampleonly, buttress assembly (3300) may be applied to deck (73) using amodified version of retainer (300) as described above; or using anyother suitable structures or techniques as will be apparent to those ofordinary skill in the art in view of the teachings herein.

4. Other Exemplary Buttress Assemblies

It should be understood that the adhesive material that removablysecures a buttress body (102) to underside (65) of anvil (60) or to deck(73) of staple cartridge (70) may have various properties includingmalleability and tackiness that provides self-attachment to underside(65) of anvil (60) or to deck (73) of staple cartridge (70). In otherwords, the adhesive material may deform to the shape presented by thecorresponding contact area of underside (65) or deck (73). It shouldalso be understood that the adhesive material may be provided onbuttress body (102) in various shapes and configurations. For instance,the adhesive material may be provided in a pattern that includesselective zones of adhesion to minimize the likelihood of collateraldamage to areas such as staple pockets (74) whose performance might beadversely affected by influx of adhesive material. The pattern of theadhesive material may also minimize the number and size of the adhesivecontact with underside (65) or deck (73), thereby minimizing the forcerequired to pull buttress assembly (100) off of underside (65) or deck(73) after end effector (40) has been actuated. The geometry of theadhesive material may provide uniform thickness or variable thickness.The adhesive material may also provide variable stiffness. Providing avariable thickness and/or variable stiffness may provide a variablepressure distribution.

FIG. 55 shows an exemplary alternative buttress assembly (3400) thatcomprises a pair of buttress bodies (3402) and an adhesive material(3410) that is positioned along the outer perimeter of the upper surface(3404) of each buttress body (3402). Buttress bodies (3402) areseparated by a gap (3406) that corresponds to channel (62) of anvil (60)and channel (72) of staple cartridge (70). A set of tethers (3420)extend transversely across gap (3406), connecting buttress bodies(3402). As described above with respect to other tethers, tethers (3420)of this example will be severed by knife member (80) when firing beam(82) is advanced distally during actuation of end effector (40). Due tothe configuration and arrangement of adhesive material (3410), buttressassembly (3400) is only adhered to underside (65) or deck (73) along theouter perimeter of buttress body (3402), which may minimize the forcerequired to pull buttress assembly (3400) off of underside (65) or deck(73) after end effector (40) has been actuated. Various suitablematerials that may be used to form buttress bodies (3402), adhesivematerial (3410), and tethers (3420) will be apparent to those ofordinary skill in the art in view of the teachings herein.

FIG. 56 shows another exemplary alternative buttress assembly (3500)that comprises a buttress body (3502) and an adhesive material (3510)that is positioned in discrete regions along the outer perimeter of theupper surface (3504) of buttress body (3502). Buttress body (3502)defines a longitudinally extending array of gaps (3506) that correspondto channel (62) of anvil (60) and channel (72) of staple cartridge (70).Buttress body (3502) further defines a set of transversely extendingbridge regions (3520) that separate gaps (3506). As described above withrespect to tethers, bridge regions (3520) of this example will besevered by knife member (80) when firing beam (82) is advanced distallyduring actuation of end effector (40). Due to the configuration andarrangement of adhesive material (3510), buttress assembly (3400) isonly adhered to underside (65) or deck (73) at discrete regions alongthe outer perimeter of buttress body (3502), which may further minimizethe force required to pull buttress assembly (3500) off of underside(65) or deck (73) after end effector (40) has been actuated. Thispull-away force may be lower for buttress assembly (3500) than it is forbuttress assembly (3400) since less adhesive material (3510) is used inbuttress assembly (3500). Various suitable materials that may be used toform buttress body (3502) and adhesive material (3510) will be apparentto those of ordinary skill in the art in view of the teachings herein.

FIG. 57 shows yet another exemplary alternative buttress assembly (3600)that comprises a buttress body (3602) with a plurality of integralreinforcement members (3610). Buttress body (3602) may be configured andoperable in accordance with any of the various buttress bodies describedherein. An adhesive material (not shown) is incorporated into buttressbody (3602) in order to provide removable attachment of buttressassembly (3600) to underside (65) of anvil (60) or deck (73) of staplecartridge (70). Various suitable compositions that may be used toprovide the adhesive material, and various suitable ways in which suchadhesive material may be incorporated into buttress body (3602), will beapparent to those of ordinary skill in the art in view of the teachingsherein.

Reinforcement members (3610) are configured to provide structuralreinforcement to buttress body (3602) and/or to the attachment ofstaples (77) that are driven through buttress assembly (3600). By way ofexample only, in some versions buttress body (3602) is formed of aporous sponge like material while reinforcement members (3610) areformed of a tight fibrous weave that has greater tensile strength thanthe material forming buttress body (3602). Various suitable materialsand structures that may be used to form reinforcement members (3610)will be apparent to those of ordinary skill in the art in view of theteachings herein. In the present example, two of the reinforcementmembers (3610) have a generally “S” shaped configuration while the othertwo reinforcement members (3610) have a generally “L” shapedconfiguration. These shapes are configured to enable each reinforcementmember (3610) to receive several staples (77) from different rows andcolumns of staple cartridge (70). By spanning across discrete sets ofstaples (77) from different rows and columns of staple cartridge (70),reinforcement members (3610) may provide greater reinforcement than whatmight otherwise be provided if reinforcement members (3610) spanned theentire array of staples (77) or just individual staples (77). Othersuitable shapes and arrangements for reinforcement members (3610) willbe apparent to those of ordinary skill in the art in view of theteachings herein. It should also be understood that reinforcementmembers (3610) may be integrated into buttress body (3602) in anysuitable fashion, including but not limited to providing reinforcementmembers (3610) between apposed layers of buttress body (3602) or formingbuttress body (3602) around reinforcement members (3610).

5. Exemplary Alternative Retainer

FIG. 58 shows an exemplary alternative retainer (3700) that may be usedwith any of the various buttress assemblies described herein. Retainer(3700) of this example comprises a base member (3752) having an uppersurface (3754), a plurality of latches (3756), and a distally projectingtongue (3758) that is configured to facilitate grasping and manipulationof retainer (3750). Retainer (3700) also includes an upper member (3760)that is secured to base member (3752) by a living hinge (3770). Uppermember (3760) has an upper surface (3762) that is configured to engagebuttress body (3702). Upper member (3760) includes a plurality ofprojections (3764) extending upwardly from upper surface (3762), andcentral rib (3766) extending upwardly and longitudinally along thelaterally central region of upper surface (3762), and a pair of outerribs (3768) extending upwardly and longitudinally along the outer edgesof upper surface (3762). While projections (3764) are shown as spanningalong only a portion of the length of upper surface (3762), it should beunderstood that projections (3764) may span along the entire length ofupper surface. It should also be understood that projections (3764) mayspan along three rows on each side of central rib (3766), correspondingto three rows of staple forming pockets (64) on underside (65) of anvil(60).

It should be understood that retainer (3700) may be removably secured toend effector (40) in a manner similar to retainer (300) described above,with latches (3756) releasably engaging lower jaw (50). At such a stage,upper member (3760) is spaced away from upper surface (3754) of basemember (3752) due to a resilient bias imposed by living hinge (3770).The resilient bias provided by living hinge (3770) may ensure that upperadhesive layer (104) of a buttress assembly (100) that is laid overupper surface (3762) will contact the appropriate region of underside(65) of anvil (60) before anvil (60) reaches a fully closed position.The resilient bias provided by living hinge (3770) may also provide andmaintain a minimum consistent pressure during the closure of anvil (60)to enhance the attachment of upper adhesive layer (104) to underside(65) of anvil (60).

As anvil (60) is driven further toward the closed position, anvil (60)bears down on upper adhesive layer (104) and upper member (3760),thereby causing upper member (3760) to pivot toward base member (3752).Adhesive layer (104) is compressed between underside (65) of anvil (60)and projections (3764). Projections (3764) provide focused pressure toregions of buttress assembly (100) at regions corresponding to stapleforming pockets (64) (and/or into other surface features of underside(65)), thereby further promoting adhesion between adhesive layer (104)and underside (65). Ribs (3766, 3768) may ensure proper lateralalignment of retainer (3700) and buttress assembly (100) with anvil (60)during the closure of anvil (60). Ribs (3766, 3768) may also preventadhesive material from entering channel (62) or escaping from sides ofanvil (60) during closure of anvil (60). When anvil (60) reaches theclosed position, latches (3768) of retainer (3700) may secure uppermember (3760) into apposition with base member (3752), facilitatingremoval of retainer (3750) from end effector (40). Buttress assembly(100) may then be left adhered to underside (65) of anvil (60), suchthat end effector (40) is then ready for use.

While retainer (3700) is described as being used in combination withbuttress assembly (100), it should be understood that retainer (3700)may be used in combination with any other buttress assembly referred toherein.

IV. Miscellaneous

It should be understood that any one or more of the teachings,expressions, embodiments, examples, etc. described herein may becombined with any one or more of the other teachings, expressions,embodiments, examples, etc. that are described herein. Theabove-described teachings, expressions, embodiments, examples, etc.should therefore not be viewed in isolation relative to each other.Various suitable ways in which the teachings herein may be combined willbe readily apparent to those of ordinary skill in the art in view of theteachings herein. Such modifications and variations are intended to beincluded within the scope of the claims.

It should be appreciated that any patent, publication, or otherdisclosure material, in whole or in part, that is said to beincorporated by reference herein is incorporated herein only to theextent that the incorporated material does not conflict with existingdefinitions, statements, or other disclosure material set forth in thisdisclosure. As such, and to the extent necessary, the disclosure asexplicitly set forth herein supersedes any conflicting materialincorporated herein by reference. Any material, or portion thereof, thatis said to be incorporated by reference herein, but which conflicts withexisting definitions, statements, or other disclosure material set forthherein will only be incorporated to the extent that no conflict arisesbetween that incorporated material and the existing disclosure material.

Versions of the devices described above may have application inconventional medical treatments and procedures conducted by a medicalprofessional, as well as application in robotic-assisted medicaltreatments and procedures. By way of example only, various teachingsherein may be readily incorporated into a robotic surgical system suchas the DAVINCI™ system by Intuitive Surgical, Inc., of Sunnyvale, Calif.Similarly, those of ordinary skill in the art will recognize thatvarious teachings herein may be readily combined with various teachingsof any of the following: U.S. Pat. No. 5,792,135, entitled “ArticulatedSurgical Instrument For Performing Minimally Invasive Surgery WithEnhanced Dexterity and Sensitivity,” issued Aug. 11, 1998, thedisclosure of which is incorporated by reference herein; U.S. Pat. No.5,817,084, entitled “Remote Center Positioning Device with FlexibleDrive,” issued Oct. 6, 1998, the disclosure of which is incorporated byreference herein; U.S. Pat. No. 5,878,193, entitled “Automated EndoscopeSystem for Optimal Positioning,” issued Mar. 2, 1999, the disclosure ofwhich is incorporated by reference herein; U.S. Pat. No. 6,231,565,entitled “Robotic Arm DLUS for Performing Surgical Tasks,” issued May15, 2001, the disclosure of which is incorporated by reference herein;U.S. Pat. No. 6,783,524, entitled “Robotic Surgical Tool with UltrasoundCauterizing and Cutting Instrument,” issued Aug. 31, 2004, thedisclosure of which is incorporated by reference herein; U.S. Pat. No.6,364,888, entitled “Alignment of Master and Slave in a MinimallyInvasive Surgical Apparatus,” issued Apr. 2, 2002, the disclosure ofwhich is incorporated by reference herein; U.S. Pat. No. 7,524,320,entitled “Mechanical Actuator Interface System for Robotic SurgicalTools,” issued Apr. 28, 2009, the disclosure of which is incorporated byreference herein; U.S. Pat. No. 7,691,098, entitled “Platform Link WristMechanism,” issued Apr. 6, 2010, the disclosure of which is incorporatedby reference herein; U.S. Pat. No. 7,806,891, entitled “Repositioningand Reorientation of Master/Slave Relationship in Minimally InvasiveTelesurgery,” issued Oct. 5, 2010, the disclosure of which isincorporated by reference herein; U.S. Pub. No. 2013/0012957, entitled“Automated End Effector Component Reloading System for Use with aRobotic System, published Jan. 10, 2013, issued as U.S. Pat. No.8,844,789 on Sep. 30, 2014, the disclosure of which is incorporated byreference herein; U.S. Pub. No. 2012/0199630, entitled“Robotically-Controlled Surgical Instrument with Force-FeedbackCapabilities,” published Aug. 9, 2012, issued as U.S. Pat. No. 8,820,605on Sep. 2, 2014, the disclosure of which is incorporated by referenceherein; U.S. Pub. No. 2012/0132450, entitled “Shiftable Drive Interfacefor Robotically-Controlled Surgical Tool,” published May 31, 2012,issued as U.S. Pat. No. 8,616,431 on Dec. 31, 2013, the disclosure ofwhich is incorporated by reference herein; U.S. Pub. No. 2012/0199633,entitled “Surgical Stapling Instruments with Cam-Driven StapleDeployment Arrangements,” published Aug. 9, 2012, issued as U.S. Pat.No. 8,573,461 on Nov. 5, 2013, the disclosure of which is incorporatedby reference herein; U.S. Pub. No. 2012/0199631, entitled“Robotically-Controlled Motorized Surgical End Effector System withRotary Actuated Closure Systems Having Variable Actuation Speeds,”published Aug. 9, 2012, issued as U.S. Pat. No. 8,602,288 on Dec. 10,2013, the disclosure of which is incorporated by reference herein; U.S.Pub. No. 2012/0199632, entitled “Robotically-Controlled SurgicalInstrument with Selectively Articulatable End Effector,” published Aug.9, 2012, issued as U.S. Pat. No. 9,301,759 on Apr. 5, 2016, thedisclosure of which is incorporated by reference herein; U.S. Pub. No.2012/0203247, entitled “Robotically-Controlled Surgical End EffectorSystem,” published Aug. 9, 2012, issued as U.S. Pat. No. 8,783,541 onJul. 22, 2014, the disclosure of which is incorporated by referenceherein; U.S. Pub. No. 2012/0211546, entitled “Drive Interface forOperably Coupling a Manipulatable Surgical Tool to a Robot,” publishedAug. 23, 2012, issued as U.S. Pat. No. 8,479,969 on Jul. 9, 2013; U.S.Pub. No. 2012/0138660, entitled “Robotically-Controlled Cable-BasedSurgical End Effectors,” published Jun. 7, 2012, issued as U.S. Pat. No.8,800,838 on Aug. 12, 2014, the disclosure of which is incorporated byreference herein; and/or U.S. Pub. No. 2012/0205421, entitled“Robotically-Controlled Surgical End Effector System with RotaryActuated Closure Systems,” published Aug. 16, 2012, issued as U.S. Pat.No. 8,573,465 on Nov. 5, 2013, the disclosure of which is incorporatedby reference herein.

Versions of the devices described above may be designed to be disposedof after a single use, or they can be designed to be used multipletimes. Versions may, in either or both cases, be reconditioned for reuseafter at least one use. Reconditioning may include any combination ofthe steps of disassembly of the device, followed by cleaning orreplacement of particular pieces, and subsequent reassembly. Inparticular, some versions of the device may be disassembled, and anynumber of the particular pieces or parts of the device may beselectively replaced or removed in any combination. Upon cleaning and/orreplacement of particular parts, some versions of the device may bereassembled for subsequent use either at a reconditioning facility, orby a user immediately prior to a procedure. Those skilled in the artwill appreciate that reconditioning of a device may utilize a variety oftechniques for disassembly, cleaning/replacement, and reassembly. Use ofsuch techniques, and the resulting reconditioned device, are all withinthe scope of the present application.

By way of example only, versions described herein may be sterilizedbefore and/or after a procedure. In one sterilization technique, thedevice is placed in a closed and sealed container, such as a plastic orTYVEK bag. The container and device may then be placed in a field ofradiation that can penetrate the container, such as gamma radiation,x-rays, or high-energy electrons. The radiation may kill bacteria on thedevice and in the container. The sterilized device may then be stored inthe sterile container for later use. A device may also be sterilizedusing any other technique known in the art, including but not limited tobeta or gamma radiation, ethylene oxide, or steam.

Having shown and described various embodiments of the present invention,further adaptations of the methods and systems described herein may beaccomplished by appropriate modifications by one of ordinary skill inthe art without departing from the scope of the present invention.Several of such potential modifications have been mentioned, and otherswill be apparent to those skilled in the art. For instance, theexamples, embodiments, geometries, materials, dimensions, ratios, steps,and the like discussed above are illustrative and are not required.Accordingly, the scope of the present invention should be considered interms of the following claims and is understood not to be limited to thedetails of structure and operation shown and described in thespecification and drawings.

We claim:
 1. An apparatus comprising: (a) an applicator; and (b) abuttress assembly configured to be releasably coupled with theapplicator prior to being coupled with one of an anvil or a deck of astapling assembly of an end effector of a surgical stapler, the buttressassembly comprising: (i) a buttress body; and (ii) an adhesive materialdisposed on the buttress body and configured to removably couple thebuttress body with one of the anvil or the deck, wherein the adhesivematerial includes a bioabsorbable polymer having an inherent viscosityat or below 3.0 dL/g, wherein the adhesive material is pressuresensitive, wherein the adhesive material is malleable at roomtemperature.
 2. The apparatus of claim 1, wherein the adhesive materialhas a non-homogenous pressure distribution when pressed against one ofthe anvil or the deck of the stapling assembly of the end effector. 3.The apparatus of claim 1, wherein the adhesive material includespressure sensitive polyurethane.
 4. The apparatus of claim 1, whereinthe adhesive material includes a putty or wax composition.
 5. Theapparatus of claim 4, wherein the putty or wax composition materialcomprises beeswax with one or more of the paraffin, petroleum jelly,isopropyl palmitate, sesame oil, carbolic acid.
 6. The apparatus ofclaim 1, wherein the inherent viscosity ranges from about 0.3 dL/g toabout 1.0 dL/g.
 7. The apparatus of claim 1, wherein the adhesivematerial has an inherent viscosity that is less than 1.0 dL/g and aglass transition temperature that is between about −10 degrees Celsiusand 10 degree Celsius.
 8. The apparatus of claim 1, wherein the adhesivematerial being malleable is configured to take the form of a surfacewith which the adhesive material is engaged, in response to pressurebeing applied to the adhesive material.
 9. The apparatus of claim 1,wherein the adhesive material includes at least one projection extendingaway from the buttress body and configured to extend within a stapleforming pocket of the anvil or a trough of the deck of the staplingassembly.
 10. The apparatus of claim 9, wherein the at least oneprojection includes a plurality of projections that are configured toextend within a plurality of staple forming pockets of the anvil. 11.The apparatus of claim 10, wherein the plurality of projections areconfigured to provide focused pressure at regions of the buttress bodycorresponding to the plurality of staple forming pockets of the anvil.12. The apparatus of claim 10, wherein the adhesive material includes abase layer with the plurality of projections extending outwardly fromthe base layer.
 13. The apparatus of claim 1, wherein the adhesivematerial has a molecular weight of about 11,000 g/mol to about 30,000g/mol.
 14. The apparatus of claim 1, wherein the adhesive materialincludes hydroxypropyl cellulose.
 15. The apparatus of claim 1, whereinthe applicator includes a retainer, the retainer comprising: (a) a bodydefining a gap configured to receive at least one of the anvil or thedeck of the stapling assembly of the end effector, and (b) a platformdisposed within the gap that supports the buttress body, wherein thebuttress body is releasably coupled with the platform prior to beingcoupled with one of the anvil or the deck of the stapling assembly. 16.The apparatus of claim 1, further comprising the surgical stapler, thesurgical stapler comprising: (a) a shaft assembly, and (b) the endeffector extending distally from the shaft assembly, the end effectorcomprising: (i) the stapling assembly that includes the deck, and (ii)the anvil that includes a plurality of staple forming pockets.
 17. Theapparatus of claim 1, wherein the applicator includes a retainer,wherein the buttress body is configured to be releasably coupled withthe retainer prior to being coupled with one of the anvil or the deck ofthe stapling assembly.
 18. An apparatus comprising: (a) a buttress body;and (b) an adhesive material configured to removably couple the buttressbody with one of an anvil or a deck of a stapling assembly of a surgicalstapler, wherein the adhesive material includes a bioabsorbable polymerhaving an inherent viscosity at or below 3.0 dL/g, wherein the adhesivematerial includes hydroxypropyl cellulose, wherein the adhesive materialis malleable at room temperature.
 19. An apparatus comprising: (a) asurgical stapler comprising: (i) a shaft assembly, and (ii) an endeffector extending distally from the shaft assembly, the end effectorcomprising: (A) a stapling assembly that includes a deck, wherein thedeck includes a trough, and (B) an anvil that includes a plurality ofstaple forming pockets; and (b) a buttress assembly comprising: (i) abuttress body, and (ii) an adhesive material configured to removablycouple the buttress body with one of the anvil or the deck of thestapling assembly, wherein the adhesive material includes abioabsorbable polymer having an inherent viscosity at or below 3.0 dL/g,wherein the adhesive material includes at least one projection extendingaway from the buttress body and configured to extend within anindividual pocket of the plurality of staple forming pockets of theanvil or the trough of the deck of the stapling assembly.
 20. Theapparatus of claim 19, wherein the at least one projection includes aplurality of projections that are configured to extend within theplurality of staple forming pockets of the anvil.